Centrifuge system utilizing disposable components and automated processing of blood to collect platelet rich plasma

ABSTRACT

A centrifugal method, and corresponding system, for processing blood to collect platelet rich plasma. A separation chamber is filled with blood from a fill syringe by rotating the separation chamber at a fill rotation rate and pumping the blood from the fill syringe. A soft spin is used to initially separate red blood cells from platelets by spinning the separation chamber at a soft spin rate. A percentage of the blood is drawn from the separation chamber back into the fill syringe to remove separated red blood cells. A second portion of the separated blood is drawn from the separation chamber until a red blood cell/platelet interface is detected. A hard spin is performed by spinning the separation chamber at a higher rate and connecting tubing is cleared of red blood cells by drawing a predetermined clearing volume. The platelet rich plasma is then collected in the collection syringe.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/388,877, filed Jun. 14, 2002, entitled “System for Producing PlateletRich Plasma,” which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to novel methods and systems for the centrifugalseparation of a liquid into its components of varying specific gravitiesand collection of these components, and more particularly, to aseparation system and method for separating blood into its componentsand collecting platelet rich plasma and other blood components usingdisposable separation containers, input and output tubing, and sourceand collection syringes and using automated operation of systemcomponents (such as a centrifuge, syringe pumps, and valves) to separatea volume of blood in a disposable separation container into itscomponents and then collect user-selected volumes and components (suchas platelet rich plasma) from the container.

2. Relevant Background

Centrifugation utilizes the principle that particles suspended insolution will assume a particular radial position within the centrifugerotor based upon their respective densities and will therefore separatewhen the centrifuge is rotated at an appropriate angular velocity for anappropriate period of time. Centrifugal liquid processing systems havefound applications in a wide variety of fields. For example,centrifugation is widely used in blood separation techniques to separateblood into its component parts, that is, red blood cells, platelets,white blood cells, and plasma.

The liquid portion of the blood, referred to as plasma, is aprotein-salt solution in which red and white blood cells and plateletsare suspended. Plasma, which is 90 percent water, constitutes about 55percent of the total blood volume. Plasma contains albumin (the chiefprotein constituent), fibrinogen (responsible, in part, for the clottingof blood), globulins (including antibodies) and other clotting proteins.Plasma serves a variety of functions, from maintaining a satisfactoryblood pressure and providing volume to supplying critical proteins forblood clotting and immunity. Plasma is obtained by separating the liquidportion of blood from the cells suspended therein.

Red blood cells (erythrocytes) are perhaps the most recognizablecomponent of whole blood. Red blood cells contain hemoglobin, a complexiron-containing protein that carries oxygen throughout the body whilegiving blood its red color. The percentage of blood volume composed ofred blood cells is called the “hematocrit.”White blood cells(leukocytes) are responsible for protecting the body from invasion byforeign substances such as bacteria, fungi and viruses. Several types ofwhite blood cells exist for this purpose, such as granulocytes andmacrophages which protect against infection by surrounding anddestroying invading bacteria and viruses, and lymphocytes which aid inthe immune defense. Platelets (thrombocytes) are very small cellularcomponents of blood that help the clotting process by sticking to thelining of blood vessels. Platelets are vital to life, because they helpprevent both massive blood loss resulting from trauma and blood vesselleakage that would otherwise occur in the course of normal, day-to-dayactivity.

If whole blood is collected and prevented from clotting by the additionof an appropriate anticoagulant, it can be centrifuged into itscomponent parts. Centrifugation will result in the red blood cells,which weigh the most, packing to the most outer portion of the rotatingcontainer, while plasma, being the least dense will settle in thecentral portion of the rotating container. Separating the plasma and redblood cells is a thin white or grayish layer called the buffy coat. Thebuffy coat layer consists of the white blood cells and platelets, whichtogether make up about 1 percent of the total blood volume. These bloodcomponents, discussed above, may be isolated and utilized in a widerange of diagnostic and therapeutic regimens. Various techniques andapparatus have been developed to facilitate the separation andcollection of blood components. The most widely used systems arecentrifugal systems, also referred to as blood-processing systems, andare usually discontinuous-flow or continuous-flow devices.

In discontinuous-flow systems, whole blood from the donor or patientflows through a conduit into the rotor or bowl where componentseparation takes place. These systems employ a bowl-type rotor with arelatively large (typically 200 ml or more) volume that must be filledwith blood before any of the desired components can be harvested. Whenthe bowl is full, the drawing of fresh blood is stopped, the whole bloodis separated into its components by centrifugation, and the unwantedcomponents are returned to the donor or patient through the same conduitintermittently, in batches, rather than on a continuous basis. When thereturn has been completed, whole blood is again drawn from the donor orpatient, and a second cycle begins. This process continues until therequired amount of the desired component has been collected.Discontinuous-flow systems have the advantage that the rotors arerelatively small in diameter but may have the disadvantage of arelatively large extracorporeal volume (i.e., the amount of blood thatis out of the donor at any given time during the process).Discontinuous-flow devices are used for the collection of plateletsand/or plasma and for the concentration and washing of red blood cells.They are used to reconstitute previously frozen red blood cells and tosalvage red blood cells lost intraoperatively. Because the bowls inthese systems are rigid and have a fixed volume, however, it has beendifficult to control the hematocrit of the final product, particularlyif the amount of blood salvaged is insufficient to fill the bowl withred blood cells.

One example of a discontinuous-flow system is disclosed by McMannis, etal., in his U.S. Pat. No. 5,316,540, and is a variable volume centrifugefor separating components of a fluid medium, comprising a centrifugethat is divided into upper and lower chambers by a flexible membrane,and a flexible processing container bag positioned in the upper chamberof the centrifuge. The McMannis, et al., system varies the volume of theupper chamber by pumping a hydraulic fluid into the lower chamber, whichin turn raises the membrane and squeezes the desired component out ofthe centrifuge. The McMannis, et al., system takes up a fairly largeamount of space, and its flexible pancake-shaped rotor is awkward tohandle. The McMannis, et al., system does not permit the fluid medium toflow into and out of the processing bag at the same time, nor does itpermit fluid medium to be pulled out of the processing bag by suction.

In continuous-flow systems, whole blood from the donor or patient alsoflows through one conduit into the spinning rotor where the componentsare separated. The component of interest is collected and the unwantedcomponents are returned to the donor through a second conduit on acontinuous basis as more whole blood is being drawn. Because the rate ofdrawing and the rate of return are substantially the same, theextracorporeal volume, or the amount of blood that is out of the donoror patient at any given time in the procedure, is relatively small.These systems typically employ a belt-type rotor, which has a relativelylarge diameter but a relatively small (typically 100 ml or less)processing volume. Although continuous-flow systems have the advantagethat the amount of blood that must be outside the donor or patient canbe relatively small, they have the disadvantage that the diameter of therotor is large. These systems are, as a consequence, large and often,are complicated to set up and use. These devices are used almostexclusively for the collection of platelets.

Continuous-flow systems are comprised of rotatable and stationary partsthat are in fluid communication. Consequently, continuous-flow systemsutilize either rotary seals or a J-loop. In many continuous-flowsystems, rotary seals are formed by a stationary rigid low frictionmember contacting a moving rigid member to create a dynamic seal, and anelastomeric member that provides a resilient static seal as well as amodest closing force between the surfaces of the dynamic seal. In othersystems, a pair of seal elements is provided having confronting annularfluid-tight sealing surfaces of non-corrodible material. These aremaintained in a rotatable but fluid-tight relationship by axialcompression of a length of elastic tubing forming one of the fluidconnections to these seal elements.

One drawback present in the above-described continuous-flow systems hasbeen their use of a rotating seal or coupling element between thatportion of the system carried by the centrifuge rotor and that portionof the system that remains stationary. While such rotating seals haveprovided generally satisfactory performance, they have been expensive tomanufacture and have added to the cost of the flow systems. Furthermore,such rotating seals introduce an additional component into the systemwhich if defective can cause contamination of the blood being processed.

One flow system heretofore contemplated to overcome the problem of therotating seal utilizes a rotating carriage on which a single housing isrotatably mounted. An umbilical cable extending to the housing from astationary point imparts planetary motion to the housing and thusprevents the cable from twisting. To promote sterile processing whileavoiding the disadvantages of a discontinuous-flow system within asingle sealed system, a family of dual member centrifuges can be used toeffect cell separation. One example of this type of centrifuge isdisclosed in U.S. Pat. No. RE 29,738 to Adams entitled “Apparatus forProviding Energy Communication Between a Moving and a StationaryTerminal.” Due to the characteristics of such dual member centrifuges,it is possible to rotate a container containing a fluid, such as a unitof donated blood and to withdraw a separated fluid component, such asplasma, into a stationary container, outside of the centrifuge withoutusing rotating seals. Such container systems utilize a J-loop and can beformed as closed, sterile transfer sets.

The Adams patent discloses a centrifuge having an outer rotatable memberand an inner rotatable member. The inner member is positioned within androtatably supported by the outer member. The outer member rotates at onerotational velocity, usually called “one omega,” and the inner rotatablemember rotates at twice the rotational velocity of the outer housing or“two omega.” There is thus a one-omega difference in rotational speed ofthe two members. The dual member centrifuge of the Adams patent isparticularly advantageous in that, as noted above, no seals are neededbetween the container of fluid being rotated and the non-movingcomponent collection containers. The system of the Adams patent providesa way to process blood into components in a single, sealed, sterilesystem wherein whole blood from a donor can be infused into thecentrifuge while the two members of the centrifuge are being rotated.However, the Adams system and the other continuous-flow systems aregenerally large and expensive units that are not intended to beportable. Further, they are also an order of magnitude more expensivethan a standard, multi-container blood collection set.

Whole blood that is to be separated into its components is commonlycollected into a flexible plastic donor bag, and the blood iscentrifuged to separate it into its components through a batch process.This is done by spinning the blood bag for a period of about 10 minutesin a large refrigerated centrifuge. The main blood constituents, i.e.,red blood cells, platelets and white cells, and plasma, havingsedimented and formed distinct layers, are then expressed sequentiallyby a manual extractor in multiple satellite bags attached to the primarybag.

More recently, automated extractors have been introduced in order tofacilitate the manipulation. Nevertheless, the whole process remainslaborious and requires the separation to occur within a certain timeframe to guarantee the quality of the blood components. This complicatesthe logistics, especially considering that most blood donations areperformed in decentralized locations where no batch processingcapabilities exist. This method has been practiced since the widespreaduse of the disposable plastic bags for collecting blood in the 1970'sand has not evolved significantly since then. Some attempts have beenmade to apply haemapheresis technology in whole blood donation. Thistechnique consists of drawing and extracting on-line one or more bloodcomponents while a donation is performed, and returning the remainingconstituents to the donor. However, the complexity and costs ofhaemapheresis systems preclude their use by transfusion centers forroutine whole blood collection.

There have been various proposals for portable, disposable, centrifugalapparatus, usually with collapsible bags, for example as in U.S. Pat.Nos. 3,737,096, or 4,303,193 to Latham, Jr., or with a rigid walled bowlas in U.S. Pat. No. 4,889,524 to Fell, et al. These devices all have aminimum fixed holding volume which requires a minimum volume usually ofabout 250 ml to be processed before any components can be collected.U.S. Pat. No. 5,316,540 to McMannis, et al., discloses a centrifugalprocessing apparatus, wherein the processing chamber is a flexibleprocessing bag which can be deformed to fill it with biological fluid orempty it by means of a membrane which forms part of the drive unit. Thebag comprises a single inlet/outlet tubing for the introduction andremoval of fluids to the bag, and consequently cannot be used in acontinual, on-line process. Moreover, the processing bag has a thedisadvantage of having 650 milliliter capacity, which makes theMcMannis, et al., device difficult to use as a blood processing device.

Hence, there remains a need for a centrifugal system for processingblood and other biological fluids that is compact and easy to use andthat does not have the disadvantages of prior-art discontinuous and/orcontinuous flow systems. Such a system preferably would automaticallyseparate the different components of whole blood that are differentiablein density and size, with a simple, low cost, disposable unit withoutthe use of rotational coupling elements. Additionally, the system wouldbe essentially self-contained and relatively inexpensive with the bloodcontacting set being disposable each time the whole blood has beenseparated.

Reference is made to the following commonly owned patent applicationswhich are incorporated by reference herein in their entirety: U.S. Ser.No. 10/116729 METHODS OF ISOLATING BLOOD COMPONENTS USING AMICROCENTRIFUGE AND USES THEREOF filed Apr. 4, 2002, now U.S. Pat. No.6,890,728; U.S. Ser. No. 09/961793 BLOOD CENTRIFUGE WITH EXTERIORMOUNTED SELF-BALANCING COLLECTION CHAMBER filed Sep. 24, 2001, now U.S.Pat. No. 6,589,153; U.S. Ser. No. 09/832711 FLEXIBLE CENTRIFUGE BAG ANDMETHODS OF USE filed Apr. 9, 2001, now U.S. Pat. No. 6,579,219; U.S.Ser. No. 09/833230 METHOD FOR HANDLING BLOOD SAMPLE TO ENSURE BLOODCOMPONENTS ARE ISOLATED filed Apr. 9, 2001, now U.S. Pat. No. 6,610,002;U.S. Ser. No. 09/833231 CENTRIFUGE CONTAINER HAVING CURVED LINEAR SHAPEfiled Apr. 9, 2001, now U.S. Pat. No. 6,582,350; U.S. Ser. No. 09/832729AUTOLOGOUS PLATELET GEL SPRAY DELIVERY SYSTEM filed Apr. 9, 2001; U.S.Ser. No. 09/832730 BLOOD CENTRIFUGE WITH AN ENHANCED INTERNAL DRIVEASSEMBLY filed Apr. 9, 2001, now U.S. Pat. No. 6,612,975; U.S. Ser. No.09/833232 MINIATURIZED BLOOD CENTRIFUGE HAVING SIDE MOUNTED MOTOR WITHBELT DRIVE filed Apr. 9, 2001, now U.S. Pat. No. 6,589,155; U.S. Ser.No. 09/832881 BLOOD CENTRIFUGE HAVING OVERHANGING DISPOSABLE BLOODCONTAINER filed Apr. 9, 2001, now abandoned; U.S. Ser. No. 09/832741HARD SHELL DISPOSABLE BLOOD RESERVOIR HAVING COMPLEX INTERNAL DESIGN FORUSE IN A CENTRIFUGE filed Apr. 9, 2001, now U.S. Pat. No. 6,596,181;U.S. Ser. No. 09/832516 BLOOD CENTRIFUGE HAVING INTEGRAL HEATING TOCONTROL CELLULAR COMPONENT TEMPERATURE filed Apr. 9, 2001, now U.S. Pat.No. 6,605,028; U.S. Ser. No. 09/832463 SYSTEM AND METHOD FOR AUTOMATEDSEPARATION OF BLOOD COMPONENTS filed Apr. 9, 2001, now U.S. Pat. No.6,790,371; U.S. Ser. No. 09/833233 BLOOD CENTRIFUGE HAVING CLAMSHELLBLOOD RESERVOIR HOLDER WITH INDEX LINE filed Apr. 9, 2001, now U.S. Pat.No. 6,835,316; U.S. Ser. No. 09/833234 SYSTEM FOR THE PRODUCTION OFAUTOLOGOUS PLATELET GEL filed Apr. 9, 2001, now U.S. Pat. No. 6,596,180;U.S. Ser. No. 09/832518 AUTOLOGOUS PLATELET GEL HAVING BENEFICIALGEOMETRIC SHAPES AND METHODS OF MAKING THE SAME filed Apr. 9, 2001; U.S.Ser. No. 09/832517 SYSTEM FOR THE PRODUCTION OF AUTOLOGOUS PLATELET GELUSEFUL FOR THE DELIVERY OF MEDICINAL AND GENETIC AGENTS filed Apr. 9,2001, now U.S. Pat. No. 6,719,901.

SUMMARY OF THE INVENTION

The present invention addresses the above problems by providing acentrifugal method for processing blood (or other fluids) in anautomated manner with ongoing self-balancing of fluids and allowingcollection of user-input volumes of platelet rich plasma (PRP) (oranother component if a fluid other than blood is processed). The methodincludes receiving a fill syringe having a volume of blood and receivinga collection syringe for use in collecting the PRP. The method continueswith filling a separation chamber with the blood in the fill syringe.The filling involves rotating the separation chamber with a centrifugeat a fill rotation rate and pumping the blood from the fill syringe(such as by using a syringe pump to operate the fill syringe) throughruns of tubing connecting the fill syringe and the separation chamber. Asoft spin is used to initially separate the denser red blood cells fromthe platelets and involves operating the centrifuge to spin theseparation chamber at a soft spin rotation rate higher than the fillrotation rate. A portion of the volume of the now separated blood (suchas about 25 percent of the fill volume) is then drawn from theseparation chamber back into the fill syringe. Typically, the centrifugeis first slowed to spin the separation chamber at a dwell rotation rate(similar to the fill rotation rate). A second portion of the separatedblood is drawn from the separation chamber until a RBC/PRP interface isdetected in the separation chamber. A hard spin is then performed byspinning the separation chamber at a rate higher than the soft spinrotation rate and the line and a portion of the separation chamber arecleared of RBC by drawing a line clearing volume into the fill syringe.The fill syringe is isolated (such as with a pinch valve) and a volumeof the PRP is collected by operating the collection syringe with asyringe pump. The PRP volume collected can be a default value or can bea volume received from an operator via a user interface. The method mayinclude collecting the remaining fluid from the separation chamber,i.e., collecting any remaining PRP and the platelet poor plasma (PPP).

In one aspect of the invention, a centrifuge is provided with automationfeatures for safe and convenient separation of blood components. Anautomated pinch valve can be used in combination with an automatedsyringe loading and unloading apparatus in order to introduce andwithdraw blood and blood components at designated points in the process.An automated centrifuge door latch can be used to prevent the centrifugedoor from being opened at improper points in the process and to indicateto the operator that the centrifuge door is closed before the centrifugeis placed into operation.

In another aspect of the invention, a centrifuge is provided in which askid plate provides a surface against which tubing extending from thecentrifuge can be prevented from twisting, binding and failing duringoperation of the centrifuge. The tubing rides on the skid plate as thecentrifuge spins in order to keep the shape of the tubing and frictionalengagement with the centrifuge such that fluid can move through thetubing into and out of a separation chamber carried by the centrifugewithout building up excess heat or affecting the function of the tubingduring the separation process. Also, the tubing is preferably lubricatedat the points of contact with the separation chamber, the skid plate andother rotating or rubbing components to prevent frictional heating whichcan cause the tubing to stretch or deform during centrifuge operation.

In another aspect of the invention, a separation chamber assembly isprovided with a tubing clamp that is used to hold a portion of thetubing on an arm centered in a stationary position over the spinningcentrifuge. The tubing clamp is preferably adapted to mate with thetubing such that the tubing is slightly compressed and reduced indiameter so as to be prevented from axial or rotational movement as thecentrifuge is spinning. The tubing clamp is inserted into a portion ofan arm that securely clamps and holds the tubing at a point that iscentered at a predetermined height above the spinning centrifuge. Thetubing clamp is positioned to provide a correct predetermined length oftubing between the centrifuge and the arm.

In another aspect of the invention, a compact centrifuge is providedthat includes both a single-sided drive belt and a double-sided drivebelt driving a compact arrangement of small pulleys. The double sideddrive belt causing the upper plate of the centrifuge to turn in the samedirection as the components that turn at one half the speed.

In another aspect of the invention, automated syringe pumps load andunload syringes inserted into the apparatus. A geared motor assemblydrives a rotating lead screw that moves a pusher mounted at the end of arod. A spring-loaded drive nut mounted on the rod rides along the leadscrew to advance and retract the rod and pusher. The spring-loaded drivenut can be disengaged by manually rotating the pusher. This allows theoperator to manually advance or retract the rod in a disengaged positionas a syringe is placed into the apparatus or removed from the apparatus.When the operator releases the pusher, the drive nut locks onto thedrive screw and will then only move when the drive motor is activated.

In another aspect of the invention, a centrifuge is provided withautomatic level detection. A sensor is operated by means of light orother energy that will travel through plastic and blood plasma but notthrough red blood cells. For example, sending and receiving fiber opticconduits terminate in lenses mounted on the housing near the centrifugeand transmit and receive light or other energy. The transmitted signalis received and transmitted into first and second light pipes carried ona caddy mounted to the centrifuge as the centrifuge rotates. Aseparation canister is mounted in the caddy with a portion of thecanister located between the first and second light pipes. When theinterface between the red blood cells and plasma in the canister movespast the location of the light pipes, the signal will be received by thesecond light pipe and transmitted back to the sensor. Once the level issensed, that signal can be used to control various aspects of automatedprocessing. For example, once the sensor detects the level of the plasmainterface, the machine can then turn the syringe pump off. Additionalsets of light pipes can also be used on the caddy at another portion ofthe separation canister.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates in block diagram form a blood separation and fractioncollection system according to the present invention;

FIG. 2 is a simplified flow chart illustrating functions performed by ablood separation system (such as the system of FIGS. 1 and 3–21) duringan exemplary separation and collection process;

FIG. 3 is an upper perspective view of a disassembled upper housingassembly of one embodiment of a separation and collection systemaccording to the present invention showing recesses for receiving andpositioning a fill syringe and a withdraw or collection syringe and acentrifuge basin in which a positioning arm is used to support andposition a tubing run of a disposable used in the system;

FIG. 4 is a lower perspective view of the upper housing assembly of FIG.3 showing the mounting of two pumps for use in automated operation ofthe fill and collection syringes positioned in the recessed surfaces inthe upper housing assembly shown in FIG. 3;

FIG. 5 is another perspective view of the upper housing assembly of FIG.3 shown with the syringe cover closed and showing the positioning of acentrifuge within the centrifuge basin and the mounting of a caddy, forsecurely retaining and accurately positioning a disposable separationchamber, onto the upper cover or top plate of the centrifuge;

FIG. 6 is a rear perspective view of the separation and collectionsystem showing the mounting of the upper housing assembly to a lowerhousing assembly that houses a controller system, a drive for thecentrifuge, and power and communication components;

FIG. 7 is an exploded view of a syringe pump used shown being installedin FIG. 4 illustrating a handle or pusher with a recessed surface forreceiving a syringe plunger end, a self-engaging drive nut controllablewith the handle for engaging a drive shaft or screw, and a pair oflimiting switches for controlling travel of the drive screw;

FIG. 8 illustrates in more detail the caddy shown in FIG. 5 illustratingthe positioning of light pipes in level detection assemblies that arealso used to physically support and position inlet/outlet ports of aseparation chamber, i.e., nipples adjacent the light pipes to facilitatedetection of interfaces between separated components or fractions;

FIG. 9 shows one embodiment of a disposable assembly for use with theseparation and collection system of FIGS. 3–6 including a separationchamber adapted for insertion on the caddy and tubing and tubingcomponents useful for connection to the tube positioning arm, for flowcontrol by the isolation valve, and for fluid connection to the fill andcollection syringes;

FIG. 10 is an enlarged view of the separation chamber of FIG. 9illustrating that the chamber is a two part chamber separated by avented cap configured to equalize and/or release gases by venting and toguide the tube of the disposable down into the upper opening of thecentrifuge and illustrating the use of a single port for concurrentfilling and withdrawing of fluids in each side of the chamber;

FIG. 11 is an enlarged view of the tube positioning arm of FIG. 3 bettershowing the tube latch that is rotatable through a horizontal groove inthe arm tip to allow positioning of a tube (and more specifically, atube clamp) within the arm and that is adapted to return to its originalposition to latch onto the tube clamp to retain and position the tube ofthe disposable in a desired position relative to the centrifuge;

FIG. 12 is an enlarged perspective view of the centrifuge of FIG. 5illustrating more clearly an upper opening or aperture and a side windowthrough which the tubing of the disposable assembly is passed prior toseparation and collection processes;

FIG. 13 is an exploded perspective view of the centrifuge of FIG. 12showing the inclusion of an upper and a lower drive belt each withdifferent installation arrangements to provide a desired rotation of thecentrifuge and showing the use of a diverter and skid plate to create atube path through the centrifuge between the upper opening and the sidewindow with curved surfaces for improving guiding the tubing of thedisposable through the centrifuge and providing a desirable contactsurface for the tubing during centrifuge rotation to reduce wear andbinding of the tube;

FIG. 14 is a partial exploded view similar to FIG. 13 illustrating adrive subassembly of the centrifuge;

FIG. 15 is a bottom view of the assembled subassembly of FIG. 14 showingthe use in one embodiment of a square drive for the centrifuge;

FIGS. 16 and 17 are partial exploded views of the drive subassembly ofthe centrifuge illustrating the use of a single-sided upper belt and atwo-sided lower belt to drive the upper portion or cover of thecentrifuge at a speed of twice the input speed and in a desireddirection;

FIG. 18 is a top view of the drive subassembly with the top drive beltinstalled showing the placement of the belt on the exterior surfaces ofthe center gear, tensioning pulley, and drive gear;

FIG. 19 is a sectional view taken at line 19—19 in FIG. 18 illustratingthe unique tube path defined in the centrifuge by the combination of thediverter, the skid plate, and the side plates; and

FIGS. 20–22 are additional perspective views of the centrifuge showinginsertion of the skid plate, skid plate side plates, and the shield witha path through the shield window being defined by the side plates andskid plate (as well as other portions of the drive subassembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Generally, the invention is directed to a blood separation andcollection system useful for automated separation of blood into itscomponent parts and for collection (based on user input) of plateletrich plasma (PRP) and, in some cases, platelet poor plasma (PPP) orwhite blood cells. In operation, the operator prepares the system byunlatching a centrifuge door and inserting a separation chamber portionof a separation and collection disposable onto a caddy mounted to thetop of a centrifuge. Tubing is included as part of the disposable forinputting or filling blood into the chamber and for withdrawing orcollecting blood components from the chamber and typically hasconnectors on one end for connecting to fill and withdraw syringes andis connected on the other ends to an inlet/outlet port on each side orhalf of the two-part chamber. The syringe connector end of the tubing isfirst advanced into an aperture in the caddy and through an upperaperture in the center of the centrifuge. A diverter in the centrifugeaperture assists in creating a tube path in the centrifuge and threadingthe tubing through the aperture to a side window in a shield or sidewallof the centrifuge. As the tubing emerges from the window, an operatorgrasps it and draws it through the window. The separation chamberportion of the disposable is snapped into a cradle on the caddy withportions, e.g., nipples, of each half or segment of the separationchamber residing between light pipes mounted within a level detectionassembly on the caddy to allow light to be passed through blood in thechamber halves to detect interfaces between separated components.

A portion of the tubing forming a loop in the separation chamberassembly is placed into a tubing trough or recess and tubing retainerson an upper surface of the caddy. A tubing clamp or connector in thetubing of the disposable that has been drawn or pulled through thecentrifuge is placed into a clamp or tube latch at an end of a tubepositioning arm extending from a wall of the centrifuge housing. The armholds the portion of the tubing retained by the tubing clamp so as toposition and support the tubing above the centrifuge and generally in aposition that is coaxial with a central axis of the centrifuge. In oneembodiment, a tapered portion of the tube clamp is lubricated prior toinsertion in the latch to control heat buildup and wear on the tubeclamp during operation of the centrifuge. The disposable includes a runof tubing above the arm and tube clamp that includes a branchconnection, such as a Y-connector, that leads to a fill tube with asyringe connector and a withdraw tube with a syringe connector. Theoperator places a portion of the fill tube above the Y-connector into anisolation valve, e.g., an electrically-activated pinch valve, that islocated adjacent to two syringe recesses in the upper housing assemblyof the device.

With a syringe cover of the upper housing assembly in the open position,the operator places a fill syringe, such as a large conventionalsyringe, containing blood in one of the syringe recesses adapted forthat size of syringe and connects the syringe to the fill tubeconnector. The operator also positions the flat end of a plunger of thefill syringe into a recessed surface of a knob or pusher portion of asyringe pump assembly. In one embodiment, the pusher or know is rotateduntil a drive nut disengages from a drive screw in the pump and then theoperator manually adjusts (e.g., pulls and/or pushes on the knob) aposition of a shaft or rod connected to the knob until the pusher orknob recessed or engagement surface is at the proper position to engagethe end of the plunger. In one embodiment, springs or other devices areused in the drive nut or elsewhere in the pump such that the recessedportion of the pusher engages the end of the syringe plunger when theoperator releases the know as the pusher is automatically returned toits operating or at-rest position and the drive nut engages the drivescrew. Similarly, an empty fill syringe, e.g., smaller conventionalsyringe is also attached to the connector of the withdraw tube andinserted into the second, smaller syringe recess. As the operatorinserts each of the syringes into the recesses, an optical syringedetector is interrupted and thereby, detects the presence of eachsyringe in the recess.

The syringe detectors are used by the system to indicate to the operatorthat the syringes are properly positioned in the recess by responding tothe interrupted detector signal to activate an indicator light on asyringe indicator display that includes LEDs or other indicatorsrepresenting each of the syringes. In most preferred embodiments,detection of the absence of either syringe in the recesses by the systemis used by a controller or control system of the separation andcollection system to initiate steps to disable the device fromoperating. The syringe cover assembly and the centrifuge cover assemblyare both then closed by the operator. A centrifuge door latch indicator,such as an LED, may be used by the control system to indicate to theoperator that the centrifuge cover has been properly latched. Similarly,an indicator on the syringe indicator display may indicate that thesyringe cover has been closed. The control system may further operate torespond to detection of the failure of the centrifuge door to latchproperly by disabling the system from operation.

The operator then employs a user interface on the centrifuge coverassembly to set a desired volume of platelet rich plasma to be deliveredinto the second, smaller syringe. The user interface includes a keypad,a display, and a series of progress LED indicators that indicate to theoperator the progress of blood processing. In one embodiment, theoperator sets the desired volume of platelet rich plasma by pushingappropriate keys on the keypad to increment or decrement a volume valuedisplayed by the control system on a screen of the display. When theamount appearing on the display screen is the amount desired by theoperator, the operator pushes a start button on the keypad. Once thestart button is pushed, separation of the blood in the fill syringe intoplatelet rich plasma (PRP) and PRP deposition into the second, smallersyringe is entirely automatic and requires no operator intervention withoperation of the centrifuge and syringe pumps being controlled by thecontrol system hardware and software. However, if the operator shoulddesire to stop the process, a stop button on the keypad can beactivated. At the conclusion of the automated process, the platelet richplasma is in the smaller syringe and the unused blood and the balance ofthe contents of the separation chamber, including the platelet poorplasma, are in the larger syringe. The operator may then remove thesmaller syringe from the system for use and also remove and discard thelarger syringe. Caps are then applied by the operator to each of thetube syringe connectors and the disposable including the separationchamber and tubing is removed from the system by reversing the processused to install it. In addition to the production of PRP, the operatorcan also recover the platelet poor plasma (PPP) separated by the system.During the automated cycle, the operator is prompted by the controlsystem via the user interface, and the operator may then elect to push aPPP button on the keypad to deliver the PPP to a third syringe that maybe installed in one of the syringe recesses.

The above description provides a brief overview of some of the uniquefeatures of separation and collection systems according to the inventionand at least provides a context for explaining in more detail separationand collection processes provided (typically automatically) by suchsystems. The following description begins with a general description ofsystems configured according to the invention with reference to FIG. 1.Referring then to FIGS. 1 and 2, a detailed explanation is provided ofseparation and collection processes of the invention stressing theunique functions and abilities of such systems in collecting desiredfractions or components from blood with a compact and easy-to-operatedevice. Once the functions and operation of systems according to theinvention is understood, the description then turns to a specificdiscussion of the physical components that are used in one exemplaryembodiment to provide the desired features and functions. In thisregard, FIGS. 3–22 illustrate in detail the components of a collectionseparation and collection system.

FIG. 1 illustrates in functional block form a blood separation andcollection system 10. As illustrated, a control system 12 is provided tocontrol automated operation of the system 10 and includes a centralprocessing unit (CPU), e.g. one or more microprocessors and/or chipsperforming the logic, computational, and decision-making functionsincluding interpreting and executing received instructions and managingdata storage. The control system 12 includes memory 16 for storingdigital information (such as user input PRP collection volumes) and aclock 18 used by the CPU 14 (or operations module 26) to measure lengthsof certain separation and collection processes, as explained in detailwith reference to FIG. 2. A user interface (UI or, in some embodiments,a GUI) 20 is provided to allow operators to monitor operations of thesystem 10 and to enter input to “program” the system 10 to performcertain operations. For example, the user interface 20 may include astart button and a stop button to control operations, a display screento allow the CPU 14 to display to the operator information regardingcurrent operations (such as time left in a specific portion of theprocess or a user-input collection volume), indicators such as LEDs toindicate operations such as whether a centrifuge or a syringe cover iscloses, a syringe is properly installed, stages of operation, and thelike, and a keypad or other input device (such as a touch screen, audiocommand input device, and other well-known input devices) to allow theoperator to enter information at prompts (such as a PRP collectionvolume, a command to collect PPP, and the like). These variouscomponents of the UI 20 may be located at different locations within thesystem 10 as appropriate, such as indicators near the device orcomponent being operated and display and input device adjacent eachother at a user-friendly or ergonomically-desirable location in thesystem 10. A UI module 22 is provided to control operation (inconjunction with CPU 14 and memory 16) of the UI 20. An operationsmodule 26 is provided to control most other operations (such asoperation of the centrifuge drive and inlet and outlet pumps) of thesystem 10. The modules 22 and 26 typically are embodied in software thatis executed by the control system 12 but may also include hardwarecomponents and in some cases, separate CPUs or processors and/or memoryare provided for each module 22, 26.

The system 10 includes a fill syringe 30 (or other fluid container) thatis typically installed manually by an operator and initially containsblood that is to be processed by the system 10. A fill pump 32 isprovided to pump fluids to and from the fill syringe 30 and is operatedby the control system 12 via signal line 34. In one embodiment, the fillpump 32 is a syringe pump connected externally to the fill syringe 30 toselectively move a syringe plunger to force fluid out of the syringe 30or to pull or draw fluid into the syringe 30. A position detector 36 isprovided to monitor for the presence of the fill syringe 30 in thesystem 10 (such as with a light or other energy beam or electricalcontacts) and transmits a signal on an ongoing basis to the controlsystem 12 and operations module 26 via signal line 38. A fill line 32(such as a single lumen tube) is used to fluidically connect the syringe30 to a centrifuge 54. An isolation valve 34 (such as a pinch valve orother useful valve arrangement) is provided to control flow in the line32 and is controlled again by the control system 12 and operationsmodule 26 via signals on line 35.

Similarly, a withdraw or collection syringe 40 is provided (andtypically installed by an operator) and is in fluid communication withthe centrifuge 54 via collection or withdraw line 48 (again, typically,single lumen tubing). The fill and collection lines 32 and 48 meet at aconnector 49 (such as a Y-connector) and become a single fluid line orfill/withdraw line 50, which in most preferred embodiments is a singlelumen tube. A withdraw or collection pump 42 is provided to draw fluidinto the syringe 40 and controlled by the control system 12 andoperations module 26 via signals on line 43. When syringes are used forsyringe 40 (instead of other containers), the pump 42 is typically asyringe pump. A position detector 44 transmits signals over line 46 tothe control system 12 (which in response operates syringe indicatorssuch as colored LEDs) in response to the presence or absence of thesyringe 40.

The centrifuge 54 is included in the system 10 to receive blood or otherfluids from the fill syringe 30 and to rotate to separate by centrifugalforces components (such as red blood cells, white blood cells, andplatelets) from the blood or other fluid and then to be configured tofacilitate selective withdrawal or collection of such separatedcomponents. The centrifuge 54 is driven by a drive assembly 58 that isselectively operated, and at desired rotation rates or speeds, by thecontrol system 12 and operations module 26 via signals on line 60.Although not shown, a velocity detector may be provided to transmitsignals in response to the rotation of the centrifuge 54 to the controlsystem 12, which can respond by increasing or decreasing the centrifugespeed to maintain the centrifuge 54 within an acceptable operationrange. The fluid line 50 is fed into the centrifuge 54 and connected toa separation chamber 56 to provide a flow path to and from theseparation chamber 56. As will be explained in detail below, theseparation chamber 54 is preferably a two-chambered or halved containerthat has a single port for inputting fluids and withdrawing fluids orseparated fractions. During operation, it is important to be able todetermine interfaces between these separated fractions or component richportions of the fluid in the chamber 56. An interface detector 62 (suchas an assembly that transmits light or other energy through the chamber56 and contained fluid) is provided to monitor separation processes andto transmit signals via line 64 to the control system 12 and operationsmodule 26 for processing and responsive control of the drive assembly 58and pumps 32, 42. To explain how the components of system 10 operate toprovide effective and selectable processing of blood or other fluidsamples, the operation of the system 10 will now be explained in detailwith reference to FIGS. 1 and 2.

A separation and collection process 80 performed according to theinvention with the system 10 or similar system is shown in FIG. 2. Asshown, the process 80 begins at 82 with loading or installing adisposable and syringes (such as fill syringe 30 containing blood to beprocessed and withdraw syringe 40 to collect PRP) and entering userinput. The disposable referred to in 82 generally includes all tubing32, 48, 50 and connectors (such as connector 49 and any tube clamps andthe like) and the separation chamber 56. In this manner, all fluidcontacting surfaces and components (including the syringes 30, 40) canreadily be removed from the system 10 after use to avoid contaminationor the need for cleaning components within the system 10. The disposableis installed by feeding syringe connectors and tubing 32, 48, 50 throughthe centrifuge 54 and positioning the chamber 56 along with a certainlength of tubing on a caddy device (explained in detail below) that ismounted to the top of the centrifuge 54. The tubing 50 is held inposition above the centrifuge 54 on latch of a positioning arm (againexplained in detail below) and the tubing 32 is connected to theisolation valve 34 and tubing 32, 48 are connected to the syringes 30,40. The syringes 30, 40 may be a number of sizes but in one embodimentare a 60 cc and a 10 cc syringe, respectively, that are inserted intorecesses in the system 10 adjacent the syringe positioning detectors 36,44. The fill syringe 30 contains a volume of blood to be processed andthe withdraw syringe 40 is empty to provide a collection receptacle forPRP during processing.

Also, at 82, an operator inputs user input such as a volume of PRP to becollected in the syringe 40 and/or a command that PPP be collected atthe end of processing. In one embodiment, messages are displayed to theoperator on an instrument display portion of the UI 20, such as in rowshaving a set character per row (e.g., 2 rows with 20 characters/row).During the process 80, the UI module 22 can operate to display a timeremaining in the overall process 80 and the PRP volume to be withdrawn(a default volume or the volume input by operator) or a PRP volumealready withdrawn (such as after completion of that withdrawal step).Operation status may also be provided on the display. Status may includemessages indicating a system error that has terminated the process(i.e., stopped the centrifuge 54, stopped both syringe pumps 32, 42,opened the isolation valve 34, and unlocked the centrifuge door orcover) and the message typically would provide an error number oridentifier and instruct the operator to contact maintenance personneland visual displays may be accompanied by audio indication of a systemerror. Messages indicating that user intervention is required are alsodisplayed on the display or elsewhere in the UI, such as load syringe,close cover(s), press start, and the like.

System status messages are also provided throughout the process 80 bythe UI module 22 on UI 20. In one embodiment, the system status messagesare displayed on the display (e.g., to indicate which operation isoccurring such as filling, withdrawing or collecting, and the like)along with progress LEDs or other indicators to give an approximation ofa portion of completion of the current step or function (such as byusing 4 LEDs that light as each fourth of the operation is completed andflash as a particular fourth of the operation is being performed).Additionally, red and green LEDs may be provided in the UI 20 to allowthe UI module 22 to report to the operator when the centrifuge cover isopen or closed, when the syringe cover is open or closed, and when thesyringes 30, 40 are properly positioned in the system 10. The UI 20 mayinclude minus and plus keys to facilitate inputting or changing the PRPcollection volume and a PPP key may be provided or an accept key toallow the user to choose to collect PPP after PRP collection iscompleted.

Returning to step 82, after the system 10 completes a self-check andperforms initialization (or after a previous separation cycle), a “STOP”button or indicator in the UI 20 is lit by the UI module 22 and theprogress LEDs are turned off. The UI module 22 displays a messageindicating that the operator is required to load the system 10 (i.e.,insert the disposable, the syringes, and close covers), enter a PRPvolume (or accept a default), and then press the “START” button or inputa start command. The PRP default volume (such as 0 to 10 cc when a 10 cccollection syringe 40 is used) is initially displayed at 82 by the UImodule 22 on the UI 20 and the operator then accepts this default orindicates a desired volume (such as by pressing arrow keys or plus/minuskeys).

The operator then presses the “START” button or otherwise initiatesfurther processing by the system 10 and a time for completion isdisplayed by the UI module 22 on the UI (based on calibration processesfor the system 10 including particular fluids and volumes) and isupdated by the UI module 22 based on actual completion times and/orbased on calculated or calibrated completion times. For example, thesystem 10 may be calibrated to perform separation and collectionprocesses in 17 minutes based on collection of a maximum volume of PRPand collection of PPP but if less PRP is desired or collection of PPP isdeleted the UI module will function to reduce the completion timedisplayed. In some embodiments, the operator is allowed to change thePRP volume at any point in the process 80 prior to collection of orcompleting collection of PRP. The control system 12 continues to monitoroperating status including position or presence of syringes and whethercovers are properly closed throughout the process 80 and when necessary,to interrupt operation such as when the syringe cover is opened duringfill or withdraw operations. The control system 12 will also verifysystem status prior to proceeding from step 82 to step 84 (such aswhether the syringes 30, 40 have been properly positioned) and if someintervention is required by the operator, the UI module 22 will operateto display the proper intervention message on UI 20.

At 84, the system 10 operates to fill the separation chamber 56 withfluids in the fill syringe 30. Initially, the UI module 22 displays amessage indicating that filling is proceeding and lights (or flashes) afirst progress LED or indication light. The operations module 26operates the drive assembly 58 to ramp the centrifuge 54 up to a dwellrate, such as 900 to 1100 revolutions per minute (RPM) or as in oneembodiment, 940 to 1060 RPM, with ramping occurring at a controlled at aspecific slew rate such as at a rate of 250 RPM/second. Concurrently,the fill pump 32 is operated by the operations module 26 to force orpump the blood from the fill syringe 30, such as at a rate up to 40ml/minute or higher, with the operations module 26 operating the pump 32until an ending-fill position is detected and a corresponding signalsent on line 34. Ending-fill position in one embodiment is detectedthrough the use of a switch in the pump that detects the position of adrive nut or a drive shaft which are linked to the end of the plunger ofthe syringe 30, with the switch being positioned and pump 32 selected toeffectively operate a particular size syringe (such as a standard 60 ccsyringe or other known size syringe having standardized dimensionsincluding syringe length and plunger positions and lengths). If theending-fill position is not detected after a set period of time (such aswithin 10 minutes), the operating module will indicate a fill syringe 30or fill pump 32 error and at least temporarily stop the process 80.After successful completion of step 84, the separation chamber 56 (andmore often, the two halves or portions of the chamber 56 that are usedto enhance self-balancing within the centrifuge) are at least partiallyfilled with blood which due to the relatively light centrifugal forcesat the dwell rate is positioned externally in the chamber halves buttypically is not separated into components. In some embodiments, wheneither syringe pump 32, 42 is operating an LED or other indicator isoperated by the control system 12 to indicate the operation of the pump32, 42.

At 86, the system 10 operates automatically (without operatorintervention) perform an initial separation of the components in theblood in the chamber 56. After the syringe 30 is emptied to a desiredlevel, a status message indicating that the current operational phase is“processing” and the second and first progress indicators are lit. Theoperations module 26 operates the drive assembly 58 up to a soft spinrate, e.g., a rate useful for creating enough centrifugal forces toseparate red blood cells (RBCs) to plasma in the outer regions orportions of the chamber halves or segments with minimal mixing of othercomponents in the heavier RBCs (such as white blood cells andplatelets). In one embodiment, the soft spin rate is selected to beabout 2800 RPM plus or minus 150 or more RPMs. Again, the change incentrifuge rotation rate is performed at a slew rate (such as less than250 RPM/second). After the soft spin rate is reached by the centrifuge54, the centrifuge 54 is operated for a length of time at the soft spinrate to achieve a desired level of initial separation. In oneembodiment, the soft spin rate is maintained for at least about 4minutes (but of course this time period can be varied to successfullypractice the invention and may vary with blood content (human versusanimal), for volumes processed and dimensions of the chamber, and toaccount for other operational factors and variables).

At 88, after the initial separation period has passed, the centrifuge 54is slowed at a slew rate (e.g., less than 250 RPM/second) to a dwellrate, e.g., about 2800 RPM plus or minus 150 RPM, to allow moreeffective withdrawal of separated fluids and components. After thecentrifuge 54 has reached the dwell rate, the fill pump 32 is operatedin the opposite direction or manner to cause fluid, i.e., RBC-richplasma, to be drawn from the separation chamber 56 (from the two ports)through the line 50 and fill line 32 into the now substantially empty,fill syringe 30. The system 10 is configured for processing a knownblood content or range of contents, and as such, a known or safepercentage of the blood sample can be withdrawn at a faster withdrawalrate without concern for detecting an interface between the RBCs and thenext fraction. For example, for human blood, the inventors havedetermined that at least 25 percent of blood sample that has beeninitially separated with a soft pack (as described for step 86) can bewithdrawn to quickly remove RBC-rich plasma. The volume to be withdrawncan vary with fill volume, i.e., safe percentage times the fill volume(such as 25 percent of about 60 cc or 15 cc).

Significantly, some embodiments of the process 80 call forself-calibration of the system 10 during the fast withdrawal of 88. Thisis an important feature of the process 80 as the system 10 can becalibrated for a particular patient or sample of blood, for a particularsystem 10 configuration (i.e., operations may slightly vary based onvariations or tolerances in the fabrication of sensor parts, centrifugeparts and operation, for different separation chambers 56, and otherparameters). Hence, self-calibration in a just-in-time fashion is oftenuseful for successfully detecting the RBC/plasma interface in thecurrent sample. As discussed above, the range of human hematocrit levelsis well documented such that it is known that the interface cannot bepresent and detected by the interface detector 62 during fast withdrawal88 (unless there is improper volumes or improper loading of the device).

Based on this fact or knowledge, self-calibration of the system 10 forthe current patient or sample is performed during fast withdrawal 88 bycollecting and analyzing sensor signal data received from an opticalsensor in the detector 62. Typically, this analysis involves estimatinga running mean and a running standard deviation (although other analysiscan be performed). Using the results of the real time analysis (i.e.,the calculated mean and standard deviation) the response of the detector62 in absence of the interface is characterized. In other works, theself-calibration process at 88 involves determining the output of theoptical sensor or other sensor in the interface detector 62 for thecurrent blood sample (or current patient), for the system 10configuration, and for the particular process 80 (e.g., in some cases,operation of a system 10 may vary slightly over its operating life).Interface detection can now be performed based on this calibrated outputsignal or expected signal based on the characterization during fastwithdrawal 88.

With the volume known by the control system 12, the fill pump 32 isoperated at 88 to withdraw this known volume (with a syringe or otherpump being used for pump 32 that is able to effectively be calibratedfor withdrawing a known volume into syringe 30), such as by withdrawingthe syringe plunger a known distance. The withdrawal can be performed inthis step 88 at a relatively fast rate, such as greater than about 30ml/minute, as an interface is not being detected and used to controloperations (but rather a movement of the syringe pump drive is used).However, the operations module 26 monitors signals from the interfacedetector 62 (e.g., the RBC to plasma interface sensor). A positivedetection or indication of the interface at this time typicallyindicates that the chamber 56 is not properly positioned or is notfilled or that there is a sensor 62 problem, which the operations module56 uses to trigger a system error (with corresponding message on thedisplay and/or termination of operations of the system 10).

After completion of the fast withdrawal of RBC, the process 80 continuesat 90 with the slow withdrawal of RBC or RBC-rich plasma from thechamber 56 using level or interface detection to provide a completionpoint. During slow withdrawal, the centrifuge 54 is maintained at thedwell rate but the speed of withdrawal of fluid and RBC is significantlyreduced to enable the RBC/plasma interface to be detected and theoperations module 26 to respond by stopping the syringe fill pump 32.The slow collection or withdraw rate is selected to minimize the risk ofwithdrawing too much fluid while still allowing efficient operations,and in one embodiment, the slow withdrawal rate is selected from therange of about 4 to 6 ml/minute by operating the fill pump 32 to movethe fill syringe 30 plunger outward at a corresponding rate. Once apositive detection is determined from the signal provided by interfacedetector 62 (which, in one embodiment, includes light pipes and/orlenses located adjacent to nipples in the chamber halves as will beexplained below), the operations module 26 stops operation of the fillpump 32 via a signal on line 34.

The level detector 62 and operations module 26 may be calibrated orprogrammed in a number of ways to “detect” the interface between theseparated RBC and plasma. In one embodiment, a trigger level orcalibration level (as discussed in step 88) is set by first detectingthe presence of a signal prior to fill when there is nothing blockingthe light or sensors. During fast withdrawal, a sensor mean signal isdetermined when it is known that RBC are adjacent the light pipes orother sensors and there is no signal being generated as the RBC blockthe light or sensing energy and then a standard deviation is determinedto evaluate the noise level seen or sensed by the detector 62. Thesensor or interface trigger level is then set at the mean plus a numberof deviations (such as 1 to 8 or more deviations) to provide a triggerlevel that has a relatively low probability of generating false positivedetects. Of course, other algorithms can be used to set the interfacebetween the RBC and plasma, and the described methods are consideredadequately broad to cover such operations.

A positive RBC/plasma interface detection then is set to occur when oneor more trigger levels are identified within a set time interval, suchas 4 trigger level signals within intervals of 30 milliseconds, 60,milliseconds, or some other useful time interval. In other words, thesystem 10 looks for a sensor response at the interface detector 62 thatcannot be accurately represented by the characterization of the signalcollected during the fast withdrawal 88, and when this occurs (or afterit occurs repeatedly), the position of the blood in the chamber 56 ismarked as the interface between the RBCs and the plasma. The intervalsare based on the rotation of the centrifuge and when light from a sourceoutside the rotating centrifuge 54 is transmitted through the lightpipes adjacent the chamber 56 (i.e., once a rotation in each pipe ortwice each rotation because of the use of a two chamber or halvedseparation chamber 56 and two sets of light pipes) and is determinedbased on the dwell rate or rotation rate of the centrifuge 56. So, at1000 RPM, one embodiment of the centrifuge 54 rotates one revolution in60 milliseconds such that the interface detector 62 is able to provide adetection signal on line 64 twice per revolution or every 30milliseconds.

Once these calibration steps are performed (and can be performed once ata first run of the system 10 or more preferably, are performed on anongoing basis each time a separation process 80 is completed to increaseaccuracy of interface detection), any positive detection of anRBC/plasma interface during slow withdrawal at step 90 is most likelybased on light of a sufficient quantity passing through the chamber 56and the fluid in the chamber 56, e.g., through PRP rather than RBC. Theuse of positive triggers in multiple or sequential time intervals (suchas 4–30 millisecond intervals or two rotations of the centrifuge 56) isuseful for more accurately positioning the interface(s) in the halves ofthe chamber 56 over the sensor or light pipe location.

The process 80 continues at 92 with operation of the isolation valve 34by the operations module 26 via a signal on line 35. The isolation valve34, e.g., a pinch valve contacting the outside walls of the tube 32, isclosed to block flow in fill line 32 and to isolate the fill syringe 30.Isolation is utilized to maintain the current location of the RBC/plasmainterface within the chamber halves, as without isolation fluidpressures and other factors may move the interface causing laterprocessing to be less effective in collecting all or a large percentageof the separated PRP with minimal inclusion of RBC. The operationsmodule 26 will not proceed further until it senses that the isolationvalve 34 has closed. At 94, the process 80 continues with additionalseparation at a hard spin rate that is higher than the soft spin rateand is selected to force the red blood cells and other components toseparate further from the platelets and to collect or pack (withoutforming a plug) within the most outer portions of the chamber 56. In oneembodiment, the hard spin rate is selected from the range of about 3500to 4000 RPM or higher and preferably about 3800 RPM. At 94, theoperations module 26 operates the drive assembly 58 to ramp up the speedof the centrifuge 56 at a slew rate (such of about 250 RPM/second) fromthe dwell rate to the hard spin rate. The level detector 62 is typicallynot used at this point to determine the amount of time to continue step94 but instead experimentation and knowledge of typical blood content(e.g., for different species such as humans, bovine, and the like) andcharacteristics and the configuration of the chamber 56 has allowed aminimum hold time to be determined. For example, the minimum hold timecan be set at about 6 minutes (or some shorter period of time) to obtaindesired levels of additional separation.

After the minimum hold time, at 96, the centrifuge speed is reduced by aslew rate down to a dwell rate (such as 1000 RPM) to facilitate removalof additional RBC and other components (such as white blood cells).Note, that in some embodiments, white blood cells are collected byutilizing only a soft spin or single spin from 0 to about 2200 RPM andmore preferably about 1200 to 2000 RPM without an additional hard spin.Once the dwell rate is obtained at the centrifuge 56, the operationsmodule 26 operates the isolation valve 34 to open to remove theisolation of the fill syringe 30 and the process 80 is not continueduntil the operations module 26 senses the isolation valve 34 has beenopened (and fluid can again be drawn into the fill syringe 30).

At 98, the line 50 (and typically portions of the chamber 56) is clearedof RBC and other undesired fractions (such as white cells). Clearing isperformed based on the removal of a line clearing volume of fluid. Theline clearing volume may be determined by a combination of volumetriccalculations for the disposable arrangement employed in the system 10,including the volume of fluid in an outer portion of the chamber 56having RBC and other undesired or non-platelet components and in thetube 50 (e.g., the tubing in the disposable between the chamber 56 andconnector 49), and experimentally collected information. In onepreferred embodiment, the line clearing volume is set at 1 ml plus orminus 0.1 ml of fluid, but the line clearing volume of course should beselected to match the disposable configuration to successfully practicethe method 80 and to collect a large of volume of “clean” PRP. Lineclearing at 98 is performed by the operations module 26 operating thefill pump 32 via line 34 to draw the line fill volume of fluid into thefill syringe 30 (and out of tube 32 and 50 and in some cases, chamber56). After withdrawing the line clearing volume, the pump 32 operationis terminated and at 100, the operations module 26 again operates theisolation valve 34 to isolate the fill syringe 30 from line 50 (and line48 and collection syringe 40).

At 102, the operation module 26 operates the system 10 to withdraw theuser input volume of PRP and at this point a third progress indicator orLED is lit on the UI 20. To collect the separated PRP, the operationsmodule 26 retrieves the user input volume of PRP and then operates thewithdraw or collection pump 42 to fill the withdraw syringe 40 (such asby moving the plunger outward) at a PRP collection rate (such as in therange of about 10 to 20 ml/minute or other useful rate). The PRPcollection at 102 is a volumetric withdraw and when the pump 42 haswithdrawn the input volume (typically 3 to 10 ml) the operation module42 terminates operation of the pump 42. The PRP collection volume ispreferably set within a range based on the input or fill volume and forthe particular blood content (e.g., human versus another species orblood content). In one implementation of the system 10, a 60 cc supplyof blood is provided which typically contains at least 10 cc of PRPafter the above described separation processes. Hence, the user inputPRP collection volume can be set at any volume less than 10 cc (or otherknown “safe” volume of PRP that is unlikely to contain any significantamount of platelet poor plasma (PPP) from the chamber 56). The PRP beingdrawn into the withdraw syringe 40 is pulled or suctioned from the tube50 and from the chamber 56 (when the collection volume is not exceededby fluid in the tube 50 which is typically the case in practice).Additionally, if an end position of the withdraw syringe 40 is detected(such as by a switch in the withdraw pump 42), the withdraw operation isalso terminated (as sometimes occurs if a the input collection volumecoincides with the volume of the syringe 40, e.g., 10 cc and 10 cc,respectively).

At 104, a fourth (and final) progress indicator or LED is lit and astatus message indicating the current phase is the emptying phase isdisplayed on the UI 20. The operation module 26 determines if theoperator has selected the optional collection of PPP, such as bypressing a PPP pause or collection button or key. If PPP collection isnot selected, the isolation valve 34 is opened to allow fluid to flow tothe fill syringe 30 and the pump 32 is operated to withdraw, such as ata rate of 40 ml/minutes or greater, the remaining (or at least a largeportion of the) fluid in the tube 50 and chamber 56, i.e., the PPP.Typically, the pump 32 is operated until the end position is detected(such as by a switch in pump 32) indicating the plunger has been fullywithdrawn (e.g., to the initial fill position). If the PPP is to becollected, the operator is allowed to open the syringe cover without anerror alarm or message and to remove the fill syringe, which containsRBC-rich fluid, and replace the syringe 30 with a PPP collection syringe(not shown in FIG. 10) in the same location and connect the syringe tothe fill line 32. The operator is then prompted on the UI 20 to pressthe “START” button to indicate that the fill syringe 30 has beenreplaced with a PPP collection syringe (or in some embodiments, toindicate that PPP has been manually withdrawn from either syringelocation 30 or 40). Once the “START” button is pressed, the operationsmodule 26 verifies that syringes 30 and 40 are loaded and if not, thenthe centrifuge 56 is slowed to a stop and the STOP light is lit. If thesyringes 30 (a PPP collection syringe) and 40 are loaded, then the pump32 operates the fill syringe 30 until the end withdrawal or end positionis reached (as sensed by a switch or other techniques) or a preset timeis reached (such as 10 minutes or less) at which point the centrifuge 56is stopped and the “STOP” indicator or button is lit to indicate the endof centrifuge, separation, and collection operations. At 106, thesyringes 30 and 40 and the disposable including chamber 56 and tubing32, 34, 50 are removed from the system 10.

The operation of the system 10 and, specifically, the centrifuge 54 andthe attached chamber 56 has been explained in terms of rotation ratesthat have proven useful for obtaining desired blood separation andfacilitating collection of portions of such separated blood. However,the specific rotation rates will likely vary with differing sizes, i.e.,diameters, of the centrifuge and/or the chamber. It should be understoodthat separation of blood is obtained by rotating the centrifuge 54 andchamber 56 at rates high enough to generate adequate centrifugal forcesto cause particles within the blood to be pushed away from the centralaxis of the centrifuge 51 within the chamber 56. Hence, it may beappropriate to provide ranges of g's that correspond to the aboverotation rate ranges or values for an embodiment of the centrifuge 54and chamber 56 that has been tested by applicants. Based oncalculations, for a chamber that has a 3-inch radius from the center tothe end of the nipple, the g's at 1000 RPM is 86, at 2000 RPM is 343, at2500 RPM is 538, at 3200 RPM is 880, and at 4000 RPM is 1375. For othersizes of the chamber 56 and/or centrifuge 54, different rotation ratesmay be required or useful in obtaining g's similar to those listed aboveto achieve a desired separation of a liquid sample such as blood.

While a number of arrangements can be used to practice the invention,FIGS. 3–22 illustrate an exemplary blood separation and collectionsystem 110 that can be used to implement the separation and componentcollection process 80 described with reference to FIG. 2. The system 110is a compact (about 18 inches wide by 13 inches in height by 17 inchesin depth) device that is designed to be self-contained, to be quiet withminimal vibration, and to provide automated processing and collection(as described for process 80). The components that contribute to thesefeatures of the system 110 are highlighted and discussed in detail inthe following paragraphs.

FIG. 3 illustrates an upper housing assembly 140 portion of the system110. The upper housing assembly 140 includes a centrifuge cover assembly114 typically formed at least partially of transparent or translucentplastic or other materials to allow processing operations to be observedby an operator. The centrifuge cover assembly 114 is mounted with pinsor fasteners 116 to the upper housing 140 to allow opening of the coverassembly 114 for insertion and removal of a separation chamber and otherportions of a disposable (e.g., tubing and a tube clamp). A cover latch156 is provided to secure the cover assembly 114 in a closed positionfor operations and in some embodiments, the cover latch 156 includes asensor for sensing when the cover assembly 114 is properly closes and totransmit a signal to a control system which responds appropriately withan error or prompt message (to close the cover 114) or with lighting ofan indicator or LED 158 to indicate the cover 114 is closed. The coverassembly 114 further includes a user interface portion 120 for providinginformation to the operator including operating status, error messages,and input prompts and for receiving operator input including PRPcollection volume and PPP collection commands. In one embodiment, theuser interface portion 120 includes a display (with or without progressLEDs) for displaying text messages and a keypad for accepting operatorinput (such as “START” and “STOP” buttons, a PPP button, and incrementalbuttons for adjusting PRP collection volume).

The cover assembly 114 provides access to a centrifuge basin 142 inwhich a centrifuge is later installed and in which the operatorpositions a separation chamber and portions of tubing of a disposable onthe chamber caddy with the tubing running through the centrifuge and outof the basin 142 to adjacent fill and withdraw syringes. As discussedabove, the system 110 is configured for detecting a RBC/PRP interface inthe later installed separation chamber and in this regard, a fiber opticassembly 150 with fiber bundles 154 is mounted within the centrifugebasin 142 with a support frame 152. The fiber optic assembly 150 ispositioned precisely within the basin 142 so as to transmit beams oflight from one bundle 154 toward the center of the basin, i.e., tocontact a light pipe on a detector assembly on the chamber caddy to passthrough the retained chamber and any fluid therein. Any light passingthrough the fluid is received by another light pipe and transmitted backto the fiber optic assembly 150 and second bundle 154 where it istransmitted for processing within the system 110 (e.g., a signalcorresponding to the strength of the energy of the received light istransmitted to the control system for processing as discussed withreference to FIG. 2 in interface or level detecting in process 80). Thefiber optic assembly 150 can include lenses that can be placed on theends of the fiber optic bundles 154 to focus the light or energy ontothe light pipes or from the light pipes (see FIG. 8 and correspondingtext for the light pipes 332 of the detection assemblies 324, 328 on thecaddy 214).

A positioning arm assembly 144 is provided to support a portion of thedisposable tubing within the basin 142 and, importantly, to position thetubing in a desired location relative to the centrifuge. In oneembodiment, the assembly 144 includes an arm 146 that is mounted withfasteners 149 to the basin 142. The arm 146 is designed to extendoutward over the centrifuge to enable it to position a vertical run ofthe disposable tubing (e.g., tubing between the centrifuge and the arm146) such that the longitudinal axis of the vertical tubing issubstantially coaxial with the central axis of the centrifuge whileallowing the tubing exiting the centrifuge to bow outward in an arc forease of rotation (with the arc extending from the tip of the arm 146 tothe exit aperture of the centrifuge). A releasable tube latch 148 isprovided in the arm 146 to allow an operator to position the tubing (andmore particularly, a tube clamp) within the latch 148 and then allow thelatch 148 to close over or engage the tube clamp (as is explained inmore detail with reference to FIGS. 9 and 11).

A syringe cover assembly 130 is mounted in the upper housing assembly140 with pins or fasteners 134 to allow an operator to open the coverassembly 130 to insert and remove fill and withdraw syringes and toposition and connect fill and withdraw lines of the disposable (notshown in FIG. 3). The cover assembly 130 is shaped with recesses toallow syringe plungers to extend outward from the upper housing assembly140 to have the ends of the plungers engaged with knobs or pushers 172,178 of syringe pumps (not shown) that are connected or driven by syringepump shafts 170, 176. A transparent or translucent window 138 isprovided in the cover assembly 130 to allow an operator to view aportion of the user interface of the system, i.e., the syringe display168 that is used to indicate the presence and proper insertion ofsyringes and to indicate whether the cover assembly 180 is closed oropen (which is sensed by detectors that transmit a signal to the controlsystem of the separation and collection system 110). The upper housingassembly 140 includes an isolation valve (or pinch valve) 166 that isconnected to tubing connected to a fill syringe (upstream of aY-connector that connects both the fill and withdraw syringe to a singletube for connection to the separation chamber as shown in FIG. 1). Thefill syringe, in some embodiments a 60 cc syringe, is installed in thehousing assembly 140 in a fill syringe recess 160 which includes asyringe detector 161 for sensing the presence of the fill syringe andproviding a corresponding signal to the control system. Similarly, thewithdraw or collection syringe is loaded into the system 110 by placingit into withdraw syringe recess 162 which also includes a syringedetector 163 for sensing the presence of the syringe in the recess 162.

FIG. 4 provides a bottom view of the upper housing assembly 140 of thesystem 110. As shown, the fiber optic bundles 154 have been installedand extend outward from the basin 142 for connection to additionalcomponents of an interface detector (such as detector 62) and arefurther braced with mounting frame 202 and fasteners 204. FIG. 4 alsoillustrates the mounting of a fill pump 180 (e.g., a syringe pump) and awithdraw or collection pump 190 on the upper housing assembly 140 withfasteners 182 and 192, respectively. The pumps 180, 190 are positionedadjacent the syringe recesses 160, 162 to allow ready engagement of thedrive portions of the pumps 180, 190 with plungers of syringes placed inthe recesses 160, 162. Each pump 180, 190 includes motor-driven drivegears 184, 194 (shown covered in FIG. 4) for accurately and selectivelymoving the shafts 170, 176 (that are connected to knobs or pushers thatmate with the plunger ends) inboard and outboard of the housing assembly140 to move the plungers in and out of the syringes to force out or drawin known volumes of liquid.

FIG. 5 illustrates additional assembly of the system 110 showing theupper housing assembly 140 with the syringe cover assembly 130 in aclosed position with the centrifuge cover assembly 114 removed, andbefore installation of the arm assembly 144. A centrifuge 210 of thesystem 110 is shown prior to insertion in the basin 142 (and mounting toa drive). A chamber caddy 214 used to support a separation chamber and aportion of the disposable tubing during processing is mounted withfasteners 216 onto the top of the centrifuge 210. As will be explainedfurther, the caddy 214 is configured to rigidly hold the chamber and toalign portions of the chamber relative to the interface detector (suchas the detector 62 of FIG. 1).

FIG. 6 illustrates further assembly of the system 110 with the mountingof the upper housing assembly 140 with fasteners 222 onto lower housingassembly 220. FIG. 6 shows the syringe pumps 180, 190 mounted onto theupper housing assembly 140 and covers 114, 130 in closed positions. Thesystem 110 includes a drive assembly 230 with a square-type drive shaft232 upon which the centrifuge 210 shown in FIG. 5 is mounted. Numerousdrive types may be used to practice the invention if selected to providethe desired rotation speeds discussed as part of the separation andcollection method 80 and to be controlled by an operations module.Preferably, the drive assembly 230 is selected to be quiet in operationwith relatively low vibration, and may utilize pancake component gearsets to achieve high ratio precision speed reductions (e.g., supportpreferred slew rates) in compact or low profile packages. A controller226 with circuitry and other hardware (such as microprocessors, memory,and the like) to provide the functions of control system 12 of FIG. 1.As such, the controller 226 is connected to the drive assembly 230, tothe pumps 180, 190, and to various sensors (including interface detectorcomponents) within the system 110 upon installation and assembly of thesystem 110.

FIG. 7 illustrates the fill pump 180 in more detail to illustrate thecomponents that allow the pump 180 to be engaged with a plunger end of asyringe and to automatically reconnect or re-engage the drive components(with the collection pump 190 being similar in configuration buttypically adapted for a smaller syringe). As illustrated, the pump 180includes two drive gears 184 selected to achieve a desired gear ratiofor moving an engaged syringe plunger at a known rate (useful forpumping processes where rates are important such as described forprocess 80 of FIG. 2). One gear 184 is attached to a drive motor 240that is rigidly mounted to a pump housing 244. The other drive gear 184is attached to the drive screw 242 which extends inward into the housing244.

An important aspect of the pump 180 is that in practice an operator isable to readily engage an end of a plunger during loading (with theplunger extended for a full syringe and inserted for an empty orpartially empty syringe) and to easily disengage the plunger from thepump 180 to remove the syringe from the system 110. To achieve thesefunctions but yet provide desired drive features, the pump 180 includesa shaft 170 upon which a pusher or knob 172 is mounted with set screw272. The knob 172 includes a planar recessed surface 270 for mating withthe relatively flat outer surface of a syringe plunger. A bushing guide276 is also mounted on the shaft 170 and at the other end of the shaft170 from the know 172 is a drive nut 280. The drive nut 280 (such as acam-type drive nut) is mounted or secured with dowel pin 288. Inoperation, the drive nut 280 is held onto the drive screw 242 andengages the drive screw 242 by the force of the springs 284. When anoperator rotates the knob 172 (such as 90 degrees), the internalconfiguration of the drive nut 280 (e.g., cams) force the springs 284 tocompress and opens the end of the nut 280 to disengage the nut 280 fromthe drive screw 242. When disengaged, the syringe is inserted in therecess (160 of FIG. 3) with the plunger extending outward from the upperhousing assembly 140 and the knob 172 can be pulled or pushed asnecessary to move the shaft 170 and drive nut 284 so as to align thesurface 270 with the plunger end. When relatively aligned, the knob 172is released which due to the expansion of the springs 284 and internalcam action of the drive nut 280 results in the shaft 170 rotating alongwith the knob 172 such that the surface 270 engages the plunger end andthe drive nut 280 engages the drive screw 242 at the present location ofthe drive nut 280. In some embodiments, the drive nut 280 is not springloaded and an operator would manually turn the knob 172 to re-engage thedrive nut 280 and drive screw 242. To allow the two end positions oftravel for the knob 172 (and attached plunger end) to be detected, thepump 180 includes two switches 250, 260 that are mounted to the pumphousing 244 with fasteners 252, 254, 256, 262, 264 and are positioned atspaced apart locations selected such that the switches contact a portionof the drive nut 280 or other portion of the shaft 170 to detect when aplunger attached to the knob 172 would be fully extended and fullyinserted. The switches 250, 260 being adapted to transmit a signal tothe controller 226 (shown in FIG. 6) when engaged or contacting thedrive nut 280 or other portion of the shaft 170 which is processed asend-of-travel signals for controlling operation of the system 110.

Referring to FIG. 8, the chamber caddy 214 shown mounted to the top ofthe centrifuge 210 in FIG. 5 is shown in more detail. As discussedpreviously, the system 110 is designed for low centrifuge rotation andseparation and as such, preferably is very well balanced. The caddy 214is configured to provide weight balancing by providing symmetric aspectsas well as weight reduction aspects useful for balancing after loadingof the disposable (chamber and tubing). The caddy 214 is also configuredfor rigidly supporting the chamber and tubing and for aligning thechamber with interface detection components. As illustrated, the caddy214 includes a base 302 with a side wall 304 and with a tube trough orrecessed surface 308 on approximately one half of the perimeter of thebase 302. As will become clear, the tubing of the disposable is shapedin an arc (see FIG. 9) that coincides with the shape and size of thetrough 308. The trough 308 acts to position and support the tubing ofthe disposable on the base 302 and also the removal of material from thebase 302 for the trough 308 acts to assist in balancing the caddy 214for enhanced rotation characteristics with the weight of the tubing andfluid in the tubing in the trough 308 being at least partiallycounterbalanced by the material remaining in the base 302 at the base ofthe wall 304 on the opposite side of the base 302 from the trough 308.Ribs (not shown) may further be added underneath or on top of the halfof the base 302 opposite the trough 308 to enhance balance of the caddy214. Retaining elements 310, 312 are provided to restrain movement ofthe disposable tubing during rotation. Two saddles 316, 318 are providedto support the two halves of the chamber and are typically formed of aresilient material that is sized slightly smaller than the chamberhalves to provide force-fit within the saddles 316, 318. A hole oraperture 320 is provided in the base 302 to provide a path for thedisposable tubing underneath the chamber when the chamber is installedin the saddles 316, 318.

The caddy 214 further includes two level detection assemblies 324, 328that are configured to position nipples of the chamber adjacent lightdetection devices and to align the light detection devices with thefiber optic assembly 150 shown in FIG. 1. The use of two detectorassemblies 324, 328 is desirable for obtaining interface detection twiceduring each rotation of the caddy 214 but in some embodiments, thedetection portions of one of the level detection assemblies 324 or 328can be removed with that assembly 324 or 328 simply acting as a supportfor the chamber and as a counterbalance for the weight of the otherassembly 324 or 328. As illustrated for assembly 324, two sections oflight pipe 332 is inserted in a detection base 334 to provide a path forlight transmitted from the fiber optic assembly 150 to travel and todirect the light through the nipple of the chamber and any fluid thereinand then be redirected outward from the assembly 214 back to the fiberoptic assembly 150. A cover 336 is placed over the light pipes 332 andattached with fasteners 338. Assembly 328 is assembled and shows theinlet and outlet 330 to and from the assembly 328 and the inlet andoutlet 331 for light to travel through the chamber nipple positioned inthe adjacent recesses portion of the assembly 328.

FIGS. 9 and 10 illustrate the disposable 340 that is used within thesystem 110 that is installed along with fill and withdraw syringes atthe start of each processing (such as processing 80) and then removedfor disposal after the completion of the process. The disposable 340includes the chamber 342 that is fabricated from a relativelytransparent plastic or other material to allow light or other energy forinterface detection to pass through its walls. The chamber 342 isconfigured for self-balancing and hence, is symmetric and divided intotwo halves or segments 344, 346. The segments 344, 346 are separated bya divider 370 that includes a vent 371 that is in communication withboth segments 344, 346 to allow gas to be vented during fill and otherprocesses. The divider 370 is shaped to allow the tube (between 366 and372 in FIG. 9) to be guided beneath the divider 370 when installed andfed through the caddy aperture 320 (shown in FIG. 8). Each chambersegment 344, 346 further includes a sloped or reduced portion 348, 350that tapers downward to concentrate the volume of separated materialshaving a smaller volume (such as PRP) to a much smaller diameter at thenipples 352, 354 to assist in RBC/PRP interface detection by light shownthrough the pipes 332 and nipples 352, 354 (and any liquid within thenipples 352, 354). In the illustrated embodiment, a single port 356, 358is provided for inputting and withdrawing fluids and fluid componentsfrom the chamber segments 344, 346. The chamber 342 is installed ontothe caddy 314 with the segments 344, 346 mating with saddles 316, 318and the nipples 353, 354 positioned within upper recessed surfaces inthe level detection assemblies 324, 328 adjacent inlet and outlet 331 oflight pipes 332.

As shown in FIG. 9, the disposable 340 includes runs of tubing, such assingle lumen plastic tubing (such as urethane tubing). At the chamber342, tubing 360, 362 is connected to the ports 356, 358 and is connectedtogether by connector 364 (e.g., a tubing tee) and another run of tube366 is connected to the connector 364. When installed on the caddy 214,the runs of tubing 360, 362 are inserted at least partially into thetrough 308 in the caddy base 302, the connector 364 is inserted inretainer 310, and the tubing run 366 is placed under retaining element312. The tubing run 366 is passed into a guide surface of the chamberdivider or cap 370 and is passed through the caddy aperture 320 andthrough the centrifuge (as will be discussed in more detail below). Thetubing 372 of the disposable 340 is linked to the tubing 366 (or is thesame tube section) and when installed exits an aperture in the side ofthe centrifuge and is drawn up vertically to a tube clamp 377 having aclamp taper or tapered section 376.

The tubing clamp 377 in one embodiment is a two part connector that whensnapped together over ends of tubing 372, 378 reduces the diameter ofthe tubing 372, 378 by applying a load or inward force around thecircumference of the tubing ends. This clamping force controls tubesliding (axially or rotationally) while the loop formed in the tubing372 is rotated by the centrifuge 210. The height, H_(CLAMP), of the tubeclamp 374 is selected to allow the disposable 340 to be fit into thesystem 110 and to engage a support arm assembly 144 while still alsoproviding enough slack to define a tubing arc external to the centrifugeto not contact the centrifuge. In one embodiment, the height, H_(CLAMP),is about 16 inches but of course will vary with centrifuge design andpositioning of the arm assembly 144 relative to the centrifuge (and forease of measurement the height, H_(CLAMP), is typically measured bymeasuring the length of the tubing 366, 372). The disposable 340 furtherincludes a run of tubing 378 from the clamp 374 to a dividing connector380 (e.g., a Y-type connector and see connector 49 of FIG. 1). Thedisposable 340 then branches to a fill line 382 with a syringe connector384 and a collection or withdraw line 386 with a syringe connector 388to allow these two branches of the disposable 340 to be readilyconnected to fill and collection syringes, respectively.

FIG. 11 illustrates in more detail the arm positioning assembly 144 thatis used in practice to support the disposable 340 by connecting to thetube clamp 374. The arm positioning assembly 144 includes an arm 146 anda latch 148. The latch 148 includes a clamp mating surface 398 and ahole 400 for pivotally mounting with pin 402 to the arm 146. The arm 146includes a tube aperture 390 for allowing the tube 372, 378 to enter thearm 146 and a front aperture 392 for receiving the tube clamp 374. Aside or horizontal latch groove 394 is provided to allow the latch to berotated about pin 402. A ball plunger 396 is provided is used such thatwhen an operator rotates the latch and inserts the tube clamp 374 theoperator can release the latch 148 and the plunger 396 automaticallyforces the latch 148 at surface 398 to contact and mate with the tubeclamp 374 just above a clamp taper 376 on the tube clamp 374. In onepreferred embodiment of the method 80 or for general practice, the taper376 is lubricated, such as with silicon oil, to reduce frictional forceswhich can cause heat build up in the tube clamp 374, binding, or otheroperational difficulties. Alternatively, the lubrication to reducefriction is provided on the skid plate 440 on at least a portion of thecontact surfaces or incorporated in the material(s) used to fabricatethe skid plate 440 or at least to manufacture contact surfaces of theskid plate 440.

In practice, operation of the system 110 is enhanced by lubricating ofthe disposable 340 tubing at mating points between rotating parts of thedisposable 340 and the other components of the system 110. These pointsare at the tube clamp 374 and below (or towards the centrifuge 210). Thelubricant may be a silicone-based lubricant or other lubricant that iscompatible with the material of the disposable 340 components and thematerials of the mating components (which are typically formed of sometype of plastic). The lubricant can be applied to the contact points ofthe disposable 340 such as at the clamp 374 and taper 376 which mateswith the latch 148 of the arm assembly 144, and portions of the tubing372, 366 that will contact the skid plate 440 and other internalportions of the centrifuge 210 on the tube path 490 or alternatively,all of the disposable 340 from the tube clamp 374 down to about theconnector 364 can be lubricated or a surface treatment can be used onthese disposable 340 components.

FIGS. 12–22 are provided to illustrate fully the details of onepreferred embodiment of the centrifuge 210 although the process 80 ofFIG. 2 can be implemented with differing centrifuge configurations. Thecentrifuge 210 is adapted to mate with the square drive shaft 232 ofdrive assembly 230 that provides an input rotation speed which isdoubled by the centrifuge 210 for a 2:1 input to output ratio.Additionally, the centrifuge 210 utilizes a unique two-belt arrangementsuch that the top plate 410 that is rigidly attached to the chambercaddy 214 is rotated in the same direction as components within thecentrifuge 210 that rotate at half the speed (e.g., the top plate 410rotates twice as fast but in the same direction as other centrifugecomponents, such as the shield 414 with window 416). The use ofbearings, use of small pulleys, and arrangement of components within thecentrifuge 210 leads to a very compact centrifuge with no external beltsor gears that runs quietly with little vibration which is very useful tomaintain alignment of the caddy 214 and retained chamber 342 with leveldetection portions of the system and reduces movement of the RBC/PRPinterface and movement of separated components among adjacent fractions,thereby enhancing collection of PRP. Importantly, a tube path 490 isprovided through the centrifuge 210 that maintains a desired shape ofthe disposable tubing for fluid flow and controls tubing twisting andbinding and reduces coefficient friction to limit heat buildup and wearto the tubing that may cause tubing failure. While these features of thecentrifuge 210 have been combined to provide a significantly improvedcentrifuge 210, it will be apparent to those skilled in the art thatsome or all of these features can be practiced separately, e.g., thecreation of a tube path with a shape that reduces wear and binding wouldbe useful in centrifuges with different gearing, belts, and driveconfigurations that centrifuge 210.

Referring first to FIG. 12, a centrifuge 210 is illustrated thatincludes a top plate or cover 410 upon which the caddy 214 is rigidlymounted to be rotated with the plate 410. The top plate 410 includes anaperture 412 through which the tubing of the disposable 340 is passedupon initial installation of the disposable 340 in the system 110 andremains during processing (such as tubing run 366, 372 shown in FIG. 9).The centrifuge 210 includes an outer shield or sidewall 414. The shield414 includes a window or opening 416 through which the tubing of thedisposable 340 is passed upon installation and remains during processing(tubing run 372 shown in FIG. 9). As will be explained in more detail, askid plate 440 and side plates 441, 442 are provided to define the tubepath (see path 490 in FIG. 19) and defines the contact and wear surfacesfor the tubing, e.g. tubing 372, when the sidewall 414 rotates.

FIG. 13 is an exploded view of the centrifuge 210. The centrifuge 210includes retaining rings 422 and a lower, fixed or stationary pulley 426with outer teeth. Adjacent the pulley 426 are two satellite pulleys 430and a tensioner 432. According to a significant aspect of the centrifuge210 is the use of a double-sided drive belt 436 that mates with thesatellite pulleys 430 and tensioner 432 with a first side of the belt436 and with the teeth of the pulley 426 with a second side of the belt436. The lower pulley assembly mates with a drive core assembly 450 withthe use of bearings and spacing discs 438. The drive core assembly 450is balanced (if appropriate) with a balancing weight 444.

To create a tube path in the centrifuge 210 and through the drive coreassembly 450, the skid plate 440 with side plates 441, 442 are mountedwithin the drive core assembly 450 with fasteners 446, 462.Additionally, diverter 454 with side plates 456, 458 are mounted in thedrive core assembly 450 with fasteners 446, 462 to provide a lower curveor elbow the tube path to redirect the tubing with a desirable roundedbend (rather than a sharp corner that could pinch flow or causeundesired wear) through the window 416. The drive core assembly 450 isencased in the shield 414 which is rigidly fastened with fasteners 462to the drive core assembly 450 and the centrifuge 210 is furtherbalanced (if necessary) with upper balancing weight 460.

An upper drive assembly is mounted on the drive core assembly 450 withdisks or spacers 466 and a top pulley 480 is slid over the center coreof the drive core assembly 450. A shaft 470 and satellite pulley 472along with a tensioner 474 are positioned adjacent the pulley 480 alongwith a spinner 476. A single-sided belt 484 is placed in contact withthe pulley 480, the satellite pulley 472, and the tensioner 474. Aretaining ring 482 is provided and the top plate 410 is positioned overthe top pulley to rest within the shield 414 but is rigidly mounted tothe top pulley 480 to rotate with the pulley 480, i.e., twice as fastbut in the same direction as the core assembly 450.

FIG. 14 provides another view of portions of the centrifuge 210illustrating the lower portion of the drive core assembly 450. As shown,disks 438 are slid over the core of the assembly 450 along with thelower pulley 426 with is attached with rings 422. The satellite pulleys430 are shown installed over bearings 438 (not visible in FIG. 14) andattached to the shaft 470 of upper pulley 472 and a shaft of the spinner476 (not shown). The core drive assembly 450 has an inner square drive451 for mating with the square of drive shaft 232 of drive 230. FIG. 14further shows the disks 466 placed over the core of assembly 450 priorto placement of upper pulley 480 followed by split ring 482. FIG. 15provides an additional view of the drive core assembly 450 after theinstallation of the pulley 426 and satellite pulleys 430 prior to theinstallation of the tensioner 432 and belt 436. This view more clearlyshows the inner square drive 451 of the core assembly 450.

FIG. 16 illustrates further the combined use of a single-sided belt 484to contact the upper pulley 480 which is attached to the upper plate410. FIG. 17 shows the lower pulley 426 and associated satellite pulleys430 and tensioner 432. The two-sided belt 436 is shown with its V-shapefor contacting the pulleys 426, 430 and tensioner with both sides. FIG.17 further shows the positioning of diverter 454 in core assembly 450.

FIG. 18 provides a view looking down onto the core drive assembly 450after installation of the upper pulley 480, tensioner 474, satellitepulley 472, and one-sided belt 484 but without showing the side shield414 or top plate 410. FIG. 19 also shows the inner square drive 451 formating with the drive shaft 232 of the drive assembly 230. The diverter454 and corresponding side plates 456, 458 along with the skid plate 440are shown installed within the core drive assembly 450, with the surfaceof 454 redirecting installed tubing through the core drive assembly 450.FIG. 19 is a sectional view of the portion of the centrifuge 210 shownin FIG. 18. As shown, the core drive assembly 450 is shown with thediverter 454 and skid plate 440 that include surfaces which define thecentrifuge tube path 490 (i.e., through the top plate aperture 412 inthe top plate 410, through the top portion of the core of the assembly450, and out the window 416 in the shield 414.

The shape of the tube path 490 (and, hence, the shape of the skid plate440 and diverter 454) is selected to provide for easy installation ofthe tubing of the disposable 340. Significantly, the tube path 490defined by the skid plate 440 and diverter 454 helps to define or formthe disposable tubing into a loop that rides on the skid plate 440during rotation of the centrifuge 210 and controls twisting, binding,and failing of the formed loop in the disposable 340. The skid plate440, and typically the diverter 454 and side plates 441, 442, 456, 458,are formed with smooth surfaces formed of delrin plastic or othermaterial that has a low coefficient of friction to minimize wear andheat build up but that is relatively tough or wear resistant to providea longer operational life for these centrifuge components. The skidplate 440, and typically the diverter 454 and side plates 441, 442, 456,458, in some embodiments, include vent holes formed by the combinationof the components or integral to these components that facilitate heatremoval from these components and particularly the skid plate 440 by airflow to maintain a lower or acceptable skid plate and other contactsurface temperature.

FIGS. 20–22 are provided to further illustrate the assembly of thecentrifuge 210 and particularly, the installation and positioning of theskid plate 440. As shown, the upper pulley 480, satellite pulley 472,tensioner 474, spinner 476, and belt 484 have been mounted on the drivecore assembly 450 in FIG. 20. The skid plate 440 is shown prior toinstallation. In FIG. 21, the skid plate 440 is shown installed withinthe core of the assembly 450 and prior to installation of side plates441, 442 (note, the curved surfaces for contacting the tubing of thedisposable 340 at the bend of the tubing in the core drive assembly 450and similar curved surfaces are provided on side plates 456, 458 usedwith the diverter 454). FIG. 22 illustrates a portion of the centrifuge210 after installation of the side walls 441, 442 and skid plate 440 anddefining a tube exit path from the window 416 in the shield 414.

The operation of the operations module 26 in connection with theinterface detector 62 has been discussed in some detail with referenceto FIG. 2. However, because sensing the RBC-PRP interface with thedetector 62 is an important feature of the invention, it may be usefulto discuss further a sensing algorithm(s) utilized within the interfacedetector 62 (which may be a separate module or a part of the controlsystem 12) along with the selective operation of the centrifuge 54 bythe control system and operation of the interface detector 62, whichincludes a light source and return light sensor, in sensing the RBC-PRPinterface within the separation chamber 56 (or more specifically, withina chamber 342 positioned within a disposable 340 as shown in FIGS.8–10).

Generally, the interface sensing algorithm operates differently duringfour phases of the system 10 operations. The phases occur duringpre-filling (pre-calibration); post filling, post RBC separation, andduring RBC fast withdrawal (calibration); post filling, post RBCseparation, and during RBC fast withdrawal (operation monitoring); andslow withdrawal of RBC (interface detection). During the first phase ofpre-calibration, the interface detector 62 detects the presence of asignal based on the transmission of light (e.g., through the light pipesand chamber on the disposable) and sensing of a portion of the lightreturning to a sensor within the interface detector 62. Typically,positive triggers (i.e., light sensor output signals above a presetlevel) will occur on a regular basis or period depending on the lightsource and the configuration of the chamber and centrifuge, e.g., every30 milliseconds or other period of time. During the second phase orcalibration phase, a calibrated trigger level is determined by thesensing algorithm by evaluating signals received when RBC is known to bein the chamber between the two light pipes and blocking the signal andcomparing any received signals or noise with the pre-calibration orchamber empty signals. Generally, the calibrated trigger levelcalculation includes determining a mean and a standard deviation of thesignals.

During the third phase or monitoring phase, the interface detector actsto detect the absences of the signal because during normal operationsthere should be no positive sensor detects (i.e., detection of sensoroutputs above the calibrated trigger level) when the RBCs are betweenthe light pipes or in the path between the light source and the lightsensor. During the fourth phase or interface detection phase, theinterface detector via the detection software or algorithm detects thepresence of PRP in the chamber between the light pipes in the disposable(i.e., in the nipple of the chambers). The detection algorithm generallyis configured to wait for a set of or number of sensor output signals tobe received above the trigger level (i.e., receipt of a set number oftrigger signals). In one embodiment, four trigger signals are receivedprior to the interface detector indicating the presence of the RBC/PRPinterface.

The following is a more detailed explanation of one useful technique ofoperating the system with the interface detector and sensing algorithmor software. Before filling of the chamber begins and while thecentrifuge is spinning at the dwell rate (e.g., 1000 RPM), the sensortrigger level is set to 1.0 Volt. After the sensor trigger level is set,the sensing software monitors the sensor detection circuitry in theinterface detector. When the chamber is empty, the sensor should triggerpositive detections synchronized with the rotation rate of thecentrifuge (e.g., at 1000 RPM, for a tested centrifuge and chamberconfiguration, there was one revolution every 60 milliseconds andbecause there are two sensor positions every revolution (as can be seenwith reference to FIG. 3 and fiber optic assembly 150 and to FIG. 8 andthe disposable 214 with level detection assemblies 324, 328), a sensordetect can occur every 30 milliseconds). Since before the chamber isfilled the light should go through the chamber walls that are made ofclear plastic or other material and through air to the sensor, thereshould be positive sensor detections every 30 milliseconds beforefilling. If there are no positive detections prior to filling, then thesensor is not working properly or there is another problem (such assomething blocking the light path) and the cycle of operation isterminated. As long as the positive triggers occur every 30 millisecondsas expected, the first phase or pre-calibration and the operating cycleof the centrifuge system is continued.

After filling and RBC separation and during the RBC withdrawal (asindicated by signals from operations module or other device in thecontrol system), the sensing software of the interface detectorevaluates the base noise level detected by the light sensor. This isaccomplished by calculating a running average and a running standarddeviation throughout the RBC withdrawal. This is preferably continuouslycalculated throughout the fast withdrawal until about one fourth of thefill or initial blood volume has been withdrawn as indicated bymonitored operation of the fill pump and signaled by the operationsmodule to the interface detector. During fast RBC withdrawal, the sensortrigger level is set by the sensing software to the calculated mean pluseight (or some other useful multiple) times the standard deviation ofthe noise level. This results in a calibrated trigger level that has avery low probability of generating false positive detects. Setting thetrigger level during RBC fast withdrawal provides a desired level ofcalibration of the system that is particular to the existing detector,centrifuge, disposable, and chamber configuration.

During RBC fast withdrawal, there should be no positive trigger detectsas RBCs are in the chamber and block the light path back to theinterface detector. If there are positive detects during this operatingphase, the operating cycle of the centrifuge is terminated based on asignal from the interface detector to the operations module. If thereare no positive detects, the operating cycle continues until completionof the fast withdrawal. At this point, the interface detector hasdetected the presence of the signal during pre-calibration orpre-filling and has correctly detected the absence of the signal duringRBC fast withdrawal. Hence, any positive detection during lateroperations such as slow withdrawal is assumed to be on light making itthrough the light pipes, the chamber walls, and plasma at a magnitudegreat enough to trip the light sensor (i.e., at a level above thecalibrated trigger level).

During slow withdrawal, the sensor software of the interface detector isused to monitor the sensor for output signals above the trigger level.Positive interface detection by the interface detector requires furtherthat the trigger signals meet the following criteria: (a) the triggerdetects are 30 or 60 milliseconds apart (or other repeating timeinterval depending on the centrifuge configuration) plus or minus atolerance (such as 5 percent) to allow for variance of the centrifugerotation rate; (b) more than four or other set number of signals abovethe trigger level have been detected; and (c) there has not been anunacceptable time gap between any 2 of the received trigger signals,such as a time gap more than 500 to 1000 milliseconds (and if such a gapoccurs, a counter is set back to zero for received positive triggerdetects). By the time slow RBC withdrawal occurs, the trigger level isset high enough to reduce the risk of noise producing a positive triggerdetect. However, the three criteria provided above also act as“secondary” filters that further reduce the risk of false positivescaused simply by signal noise.

When the interface detector receives and identifies a required number ofpositive trigger signals within a required period of time, the interfacedetector transmits an interface detection signal to the operationsmodule, which responds by topping slow withdrawal and the RBC-PRPinterface is now within the sensor assembly light path, i.e., within thechamber between the light paths in the light detection assembly of thedisposable. A known and fixed volume of RBC is then withdrawn to clearthe chamber and fill line(s) of RBC and allow the withdrawal of plasma.While the specific values of sensor outputs may vary significantly topractice the invention, one tested interface detector, disposable, andchamber arrangement resulted in sensor output with an empty chamber(e.g., during pre-fill) of about 1.8 volts, in sensor output with RBCsin the sensor light path of about 0.480 volts (which represents noiselevels detected by the sensor), and in sensor output through plasma (orat an RBC-PRP interface) of between about 1.0 and 1.4 volts.

Although the invention has been described and illustrated with a certaindegree of particularity, it is understood that the present disclosurehas been made only by way of example, and that numerous changes in thecombination and arrangement of parts can be resorted to by those skilledin the art without departing from the spirit and scope of the invention,as hereinafter claimed. For example, embodiments using a 60 cc fill orsupply syringe and a withdraw or collection volume of 3 to 10 cc into a10 cc syringe were discussed in detail to fully explain the functioningof separation and collection systems according to the invention, butthose skilled in the art will readily understand that numerous othersizes and volumes of syringes may be used to practice the invention andthat a number of the process steps (described with reference to FIG. 2)may be varied to better suit these different volumes. Significantly, theabove embodiments of the invention are configured to use low centrifugalforces and lower centrifuge speeds to control plugging of separated RBCsand other components in the separation chamber and its ports. With theseparated components not as tightly packed, however, the operations hadto better controlled and vibration tightly controlled and theseattributes were achieved by the described arrangements and combinationsof features and processes that led to reduced vibration of thecentrifuge, alignment of components and particularly of the chamber andthe interface optics to detect the RBC/PRP interface, and self-balancingof the fluid in the system and of the balancing of the rotatingcomponents.

When the disposable 340 is installed on the arm assembly 144 and withinthe caddy 214 and centrifuge 210, a loop is formed in part due to theskid plate 440 (and tube path 490) and an arc is defined between thewindow 416 in the shield 410 of the centrifuge 210 and the latch 148 onthe arm assembly 144. The loop is unsupported or unrestrained and passesthrough the center of the centrifuge 210 up to the connector or T 364.When the centrifuge 210 rotates, the loop is forced outward or away fromthe rotating centrifuge 210 and pulls downward on the tubing runs 366,360, 362 and, significantly, on the disposable chamber 342. Without thisdownward force on the chamber 342, the chamber 342 may, in some cases,move slightly within the caddy 214, but the design of the disposable 340and combined design of the caddy 214, centrifuge 210, and arm assembly144 provide adequate restraining forces that are useful for aligning thechamber 342 within the caddy 214 and relative to interface sensors.

1. A centrifugal method of processing a fluid having red blood cells andplatelets dispersed therein and of collecting a volume of the fluidbeing rich with the platelets which are less susceptible to centrifugalforces than the red blood cells, comprising: receiving a fill devicecontaining a fill volume of the fluid having red blood cells andplatelets and a collection device for storing the collected volume ofthe fluid being rich with the platelets; filling a separation chamberwith the fluid having red blood cells and platelets including pumpingthe fluid having red blood cells and platelets from the fill devicethrough a fluid connection line to the separation chamber, whereinduring the filling the separation chamber is rotated by a centrifuge ata fill rotation rate; performing a soft spin to first separate the redblood cells from the platelets in the fluid by operating the centrifugeto spin the separation chamber at a soft spin rotation rate; firstwithdrawing a first volume of the fluid from the separation chamber toremove a first portion of the red blood cells, the first withdrawingincludes pumping a fast withdraw volume of the fluid with the red bloodcells away from the separation chamber, the first withdrawing includesdetermining a calibrated output signal from a sensor proximal theseparation chamber during the fast withdraw volume pumping; secondwithdrawing a second volume of the fluid from the separation chamber toremove a second portion of the red blood cells, wherein the secondwithdrawing includes monitoring the separation chamber via the sensorfor an interface between the red blood cells and the platelet richvolume in the fluid, and pumping the second volume of the fluid awayfrom the separation chamber until the interface is detected, wherein theinterface monitoring includes comparing signals received from the sensorwith the calibrated output signal during fluid pumping of the secondvolume, pumping a line clearing volume of the fluid from the separationchamber and the fluid connection line to remove remaining fluidcontaining the red blood cells from the separation chamber and the fluidconnection line; and collecting the collection volume of the fluid richwith the platelets by pumping the fluid with the platelets from thefluid connection line and the separation chamber into the collectiondevice until the collection volume has been received in the collectiondevice.
 2. The method of claim 1, further including selecting thecollection volume at a user interface.
 3. The method of claim 1, furtherincluding mounting the separation chamber on the centrifuge andconnecting the fluid communication line to the fill and collectiondevices.
 4. The method of claim 3, wherein the fill and collectiondevices are syringes and wherein the separation chamber filling, thefirst withdrawing, the second withdrawing, and the line clearing pumpinginclude selectively operating a syringe pump connected to the filldevice and the collecting includes selectively operating a syringe pumpconnected to the collection device.
 5. The method of claim 1, whereinthe fluid having red blood cells and platelets dispersed therein isblood.
 6. The method of claim 1, further including after the secondwithdrawing and prior to the line clearing pumping, operating thecentrifuge to spin the separation chamber at hard spin rotation ratethat is higher than the soft spin rotation rate.
 7. The method of claim6, wherein the soft spin rotation rate is selected from the range ofabout 2000 to 3200 RPM or to achieve about 343 to about 880 g's withinthe separation chamber and the hard spin rotation rate is selected fromthe range of about 3200 to 4000 RPM or to achieve about 880 to about1375 g's within the separation chamber.
 8. The method of claim 6,wherein the soft spin rotation rate is selected from the range of about1000 to 2000 RPM or to achieve about 86 to 538 g's within the separationchamber.
 9. The method of claim 6, further including prior to the hardspin operating, isolating the fill device and including after the hardspin operating, operating the centrifuge to spin the separation chamberat about the fill rotation rate and removing the fill device isolation,and further including after the line clearing pumping, isolating thefill device.
 10. The method of claim 1, wherein the filling, the softspin performing, the first withdrawing, the second withdrawing, the lineclearing pumping, and the collecting are controlled automatically by acontrol system.
 11. A separation and collection system for processingblood to collect platelet rich plasma (PRP), comprising: a first pumpingdevice for inputting a volume of blood from a first container; aseparation container coupled to the first pumping device for containingthe input volume of blood, the separation container being adapted forbalanced spinning at rotation rates adequate to separate the blood intored blood cell (RBC), PRP, white blood cells, and platelet poor plasma(PPP) and the separation container including two ports for receiving theinput volume of blood and for withdrawing the RBC, the PRP, the whiteblood cells, and the PPP; a centrifuge device for selectively rotatingthe separation container at a plurality of processing rotation speeds; asecond pumping device coupled to the separation container forselectively withdrawing the PRP from the separation container; a secondcontainer coupled to the second pumping device for collecting the PRPwithdrawn from the separation container; flexible tubing coupled to thefirst pumping device for transferring the blood between the firstcontainer and the separation container and coupled to the second pumpingdevice for transferring the PRP between the separation container and thesecond container; and a loop device to enhance rotation and wearcharacteristics of the flexible tubing, the loop device includingcontact surfaces configured for reduced wear of portions of the flexibletubing abutting the contact surfaces, wherein the flexible tubingfurther includes a tube clamp for joining two portions of the flexibletubing and wherein the loop device includes an arm assembly including alatch for mating with and supporting the tube clamp and an arm forpositioning the latch a distance from the centrifuge, the latch beingpositioned such that the tube clamp is positioned on the rotation axisof the centrifuge.
 12. The system of claim 11, further including acontroller for controlling operations of the first pumping device thecentrifuge device, and the second pumping device and for controllingtiming of the operations.
 13. The system of claim 12, wherein thecontroller includes an operations module communicatively linked to thefirst pumping device, the centrifuge device, and the second pumpingdevice to monitor the controlled operations and includes a userinterface for receiving a user-input collection volume defining a volumeof the PRP to collect with the second pumping device, and furtherwherein the operations module operates the second pumping device towithdraw the user-input collection volume of the PRP.
 14. The system ofclaim 11, wherein the first pumping device is a first syringe pump, thesecond pumping device is a second syringe pump, the first container is afirst syringe and the second container is a second syringe.
 15. Thesystem of claim 14, wherein the system is a compact, automated systemfor collecting platelet rich plasma from a patient's blood byautomatically removing the patient's blood from the first syringe andreturning platelet rich plasma made from the patient's bloodautomatically into the second syringe.
 16. The system of claim 14,wherein the system is a compact, automated system for collectingplatelet rich plasma and platelet poor plasma from a patient's blood,the system further comprising: automatically delivering the patient'sblood from the first syringe into the separation chamber; automaticallyseparating the blood into red blood cell, platelet rich plasma, whiteblood cell, and platelet poor plasma; automatically delivering plateletrich plasma separated from the patient's blood into the second syringe;and automatically delivering platelet poor plasma separated from thepatient's blood into a third syringe coupled to the separation chamber.17. A separation and collection system for processing blood to collectplatelet rich plasma (PRP), comprising: a first pump for inputting avolume of blood; a separation chamber coupled to the first pump forcontaining the input volume of blood, the separation chamber beingadapted for balanced spinning at rotation rates adequate to separate theblood into red blood cell (RBC), PRP, white blood cells, and plateletpoor plasma (PPP) and the separation chamber including two ports forreceiving the input volume and for withdrawing the RBC, the PRP, thewhite blood cells, and the PPP; a centrifuge for selectively rotatingthe separation device at a plurality of processing rotation speeds; asecond pump for withdrawing the RBC, the PPP, the white blood cells, andthe PRP from the separation chamber; a collecting container coupled tothe second pump for collecting the PRP from the separation chamber;flexible tubing for transferring the blood between the first pump andthe separation chamber and for transferring the PRP between theseparation chamber and the collecting container, wherein the flexibletubing is connected to the first pump, the separation chamber, thesecond pump and collecting container and wherein the centrifuge includesa drive assembly for rotating the separation chamber about a rotationaxis of the centrifuge; and a loop device for creating a loop in theflexible tubing to enhance rotation and wear characteristics of theflexible tubing, the loop device including contact surfaces configuredfor reduced wear of portions of the flexible tubing abutting the contactsurfaces, wherein the flexible tubing further includes a tube clamp forjoining two portions of the flexible tubing and wherein the loop deviceincludes an arm assembly including a latch for mating with andsupporting the tube clamp and an arm for positioning the latch adistance from the centrifuge, the latch being positioned such that thetube clamp is positioned on the rotation axis of the centrifuge.
 18. Aseparation and collection system for processing blood to collectplatelet rich plasma (PRP), comprising: means for inputting a volume ofblood; means for containing the input volume of blood, the containingmeans being adapted for balanced spinning at rotation rates adequate toseparate the blood into red blood cell (RBC), PRP, white blood cells,and platelet poor plasma (PPP) and the containing means including twoports for receiving the input volume and for withdrawing the RBC, thePRP, the white blood cells, and the PPP; means for selectively andcontrollably rotating the containing means at a plurality of processingrotation speeds; means for selectively withdrawing and collecting theRBC, the PPP, the white blood cells, and the PRP from the containingmeans, wherein the withdrawing and collecting means includes a pumpingdevice and one or more collecting containers; means for transferring theblood between the inputting means and the containing means and fortransferring the RBC, the PPP, the white blood cells, and the PRPbetween the containing means and the withdrawing and collecting means,wherein the transferring means includes flexible tubing connected to theinputting means, the containing means, and the withdrawing andcollecting means and wherein the rotating means comprises a centrifugeand a drive assembly rotating the centrifuge about a rotation axis; andmeans for defining a loop in the transferring means to enhance rotationand wear characteristics of the transferring means, the loop definingmeans including contact surfaces configured for reduced wear of portionsof the transferring means abutting the contact surfaces, wherein thecentrifuge includes a top aperture with a center coinciding rotationaxis of the centrifuge, a hollow drive core with an opening adjacent thetop aperture, and a shield with a wall having a window providing accessto the drive core, and wherein the loop defining means includes a skidplate positioned within the drive core and having a curved contactsurface for contacting the flexible tubing during rotation of therotating means.
 19. The system of claim 18, wherein the loop definingmeans further includes a deflector positioned within the drive coreopposite the skid plate and having a curved contact surface, the twocurved contact surfaces of the skid plate and the diverter defining acurved elbow in a tube path through the drive core.
 20. The system ofclaim 18, wherein the flexible tubing includes a surface treatment toreduce coefficient of friction between the flexible tubing and matingsurfaces of the system.
 21. The system of claim 18, wherein the skidplate includes a surface treatment to reduce coefficient of frictionbetween the flexible tubing and mating surfaces of the system.
 22. Thesystem of claim 18, further including means for selectively isolating aportion of the inputting means and the withdrawing and collecting means.23. The system of claim 18, further including means for detecting aninterface in the containing means between the RBC and the PPP.
 24. Aseparation and collection system for processing blood to collectplatelet rich plasma (PRP), comprising: means for inputting a volume ofblood; means for containing the input volume of blood, the containingmeans being adapted for balanced spinning at rotation rates adequate toseparate the blood into red blood cell (RBC), PRP, white blood cells,and platelet poor plasma (PPP) and the containing means including twoports for receiving the input volume and for withdrawing the RBC, thePRP, the white blood cells, and the PPP; means for selectively andcontrollably rotating the containing means at a plurality of processingrotation speeds; means for selectively withdrawing and collecting theRBC, the PPP, the white blood cells, and the PRP from the containingmeans, wherein the withdrawing and collecting means includes a pumpingdevice and one or more collecting containers; means for transferring theblood between the inputting means and the containing means and fortransferring the RBC, the PPP, the white blood cells, and the PRPbetween the containing means and the withdrawing and collecting means;means for defining a loop in the transferring means to enhance rotationand wear characteristics of the transferring means, the loop definingmeans including contact surfaces configured for reduced wear of portionsof the transferring means abutting the contact surfaces; means fordetecting an interface in the containing means between the RBC and thePPP; and means for calibrating the detecting means during operation ofthe means for selectively withdrawing and collecting to withdraw theRBC, the calibrating means being adapted for determining a calibratedoutput signal from a sensor in the detecting means and the detectingmeans being operable for comparing the calibrated output signal to laterreceived signals from the sensor.
 25. A separation and collection systemfor processing blood to collect platelet rich plasma (PRP), comprising:means for inputting a volume of blood; means for containing the inputvolume of blood, the containing means being adapted for balancedspinning at rotation rates adequate to separate the blood into red bloodcell (RBC), PRP, white blood cells, and platelet poor plasma (PPP) andthe containing means including two ports for receiving the input volumeand for withdrawing the RBC, the PRP, the white blood cells, and thePPP; means for selectively and controllably rotating the containingmeans at a plurality of processing rotation speeds; means forselectively withdrawing and collecting the RBC, the PPP, the white bloodcells, and the PRP from the containing means, wherein the withdrawingand collecting means includes a pumping device and one or morecollecting containers; means for transferring the blood between theinputting means and the containing means and for transferring the RBC,the PPP, the white blood cells, and the PRP between the containing meansand the withdrawing and collecting means; means for defining a loop inthe transferring means to enhance rotation and wear characteristics ofthe transferring means, the loop defining means including contactsurfaces configured for reduced wear of portions of the transferringmeans abutting the contact surfaces; and a caddy mounted on an outputrotation surface of the rotating means for supporting and positioningthe containing means during operation of the rotating means, wherein thecaddy includes a level detection assembly including a support forsupporting a portion of the containing means and including means fordirecting light received from a source through the portion of thecontaining means and back toward the light source.
 26. The system ofclaim 25, wherein the caddy includes a pair of saddles for receiving andat least partially retaining the containing means, a recessed surfaceabout a portion of the periphery of the caddy sized to receive a portionof the transferring means, and an aperture between the saddles throughwhich the transferring means is passed.